[azylman]

No comments on emergency situations, but wanted to call out one thing:

> You need additional highways (aka: additional offramps) to truly scale day-to-day traffic

Additional highways are at-best a stop-gap for day-to-day traffic, never a solution, due to induced demand [1]. You really need large-scale investments in public transportation for this.

[1] https://en.wikipedia.org/wiki/Induced_demand#Effect_in_trans...

[whatshisface]

I've never understood how inducing demand doesn't count as success. That means people want to use the road, doesn't it? It's almost like saying that releasing new software doesn't do anything to help users, because it increases the demand for software by the virtue of its own utility more than it reduces the demand for software by keeping people busy.

[Ajedi32]

There was an article[1] posted here a while back which changed my perspective on this issue.

Indeed, there's nothing wrong with induced demand on its own. In any other market, more demand induced by lower costs (whether those costs be monetary or in the form of commute times) would almost certainly be a good thing. The only reason it's a potential issue for roads is that road use is an externality.

Building and maintaining efficient roadways comes at a significant cost, but our current system of road construction funded primarily by income taxes means road users don't pay that cost in a manner proportional to their use of those roads. Road construction is "free" from their perspective, so there's no incentive to use alternative means of transportation even if those alternatives would be superior overall once road construction and maintenance costs were factored in.

Because of this it's hard to be sure whether the demand induced by increased supply of roadways is worth the cost in any particular instance. It could be a worthwhile increase in utility, or it could just be a waste of money.

[1]: https://news.ycombinator.com/item?id=28320834

[efxhoy]

The canonical economist solution to this is to introduce road tolls. Make drivers pay at point of use to fund the road.

[ravel-bar-foo]

We already have this in the form of gas taxes. However, increasing them is politically untenable.

[bobthepanda]

Gas taxes are becoming less of this, though, partially because cars have become more fuel efficient, partially because some cars don't even use gas, and partially because the gas tax has not been raised since 1993 and so has not covered full road spending for a long time.

The most "fair" way to do it would be to charge according to road wear and tear, which would look something like axle load ^2 * miles driven, but this would be hard to implement and also widely unpopular with huge swathes of the population (truck driver is the most common profession in many states)

[efxhoy]

An important distinction between specific tolls per road and a general gas tax is that a gas tax funds all roads, not the specific one you're driving on. A toll on a particular road is an informative signal to the market of which particular stretch of road you want to drive on, in theory allowing more "efficient" allocation of roads.

[BoiledCabbage]

> Indeed, there's nothing wrong with induced demand on its own. In any other market, more demand induced by lower costs (whether those costs be monetary or in the form of commute times) would almost certainly be a good thing.

The "purpose" of expanding lanes and building alterntae highways is to improve efficiency. For people living in a given area, reduce their time spent commuting. There is large economic cost to having large portions of your population spent 10+ of their waking time commuting to and from work each weekday.

The problem with induced demand is that yes you increase capacity and more people then move clogging up the roads until a similar equilibrum is reached as before. A much better option is both expanding the number of people that can commute by living further out, and reducing the per individual commute time by mass transit. That's the true goal.

[Ajedi32]

> The problem with induced demand is that yes you increase capacity and more people then move clogging up the roads until a similar equilibrum is reached as before.

That's still an improvement over the previous status quo. Commute times are not the only, or even necessarily the most important factor in a transportation system. Your new equilibrium transports a larger number of people than the previous equilibrium. In isolation, that's purely a good thing.

In a world where road users paid for those improvements directly in proportion to their use of the road we could just keep expanding capacity indefinitely until either all the latent demand were met, or until rising construction costs drove demand down to a level where the roads were no longer congested. Since roads are funded by income taxes though, a crucial half of that feedback loop is missing. We can't just keep expanding because there's nothing to stop road users from demanding more and more capacity even after adding that capacity becomes cost-prohibitive.

[BoiledCabbage]

Yes, but that's conveniently ignoring all of the negative externalities produced by it.

So adding roads gets half the benefits (as it doesn't gain any efficiency benefits), and comes with a ton of externalities when compared to mass transit.

[Ajedi32]

What externalities, other than the one I already explained?

Only one I can think of is pollution, but that's not even caused by roads, it's caused by burning gasoline.

[onecommentman]

Or by reducing/rescheduling travel demand by work-from-home, flexible hour hours, and/or devolution of Fed agency HQs to less crowded/costly US regions where their responsibilities better match the activities/needs. Say, moving Fisheries to where they fish, Bureau of Mines to where they mine, DoE to where either energy production or demand is greatest, etc. and keep a skeleton crew of critical Fed functions like White House, Congress, Supreme Court and the Pentagon in The DC area. Perhaps a movable feast with Agencies moving every 25 years to get a fuller outside-the-Beltway American perspective. Like, say, using IT to make that happen…

[ajkjk]

There is a large human cost to having large portions of your population commuting too much, also. I always think it's weird that we tend to justify policy only in terms of its economic (or health) impacts when it is something that people just want for their quality of life.

[nostromo]

Yeah, they're shifting the goal posts.

Here in city (Seattle) most people drive because transit tends to be spotty and slow for most people.

So, what's the solution? Make driving worse of course. Speedbumps everywhere. Change 4-lane roads to 2-lanes. Remove parking. Lower speed limits to absurd levels. Make through streets dead ends.

Transit still mostly sucks, but now driving sucks too. Success!

I love transit and want more of it, but the transit folks realized it's hard to compete with driving, so they've just given up entirely on making transit great. It's easier to ruin driving.

[dont__panic]

This is a really good point, but I also want to bring up a (small) counterargument:

I live in Denver, CO. Cars basically make it impossible to walk around most of the city, even in the more residential areas. Walking is an essential part of the public transit/non-car transportation experience because essentially everyone has to walk a few blocks from a bus stop, train station, bike rack, etc. to complete their trip on both ends. If walking those few blocks is unpleasant, unsafe, or impossible, people will (reasonably) prefer cars.

Unfortunately, car and pedestrian traffic are at odds in most cities. Situations that seem better for cars (turning lanes, right-on-red, faster speed limits, street parking) often make life hell for pedestrians who try to cross the road. Or make life very, very noisy for pedestrians who need to walk or live or work near those roads.

I agree wholeheartedly that we can't just make driving suck to encourage more people to walk or take public transit. But there are aspects of driving that need to be sacrificed to make public transit better. A great example: changing 4-lane roads to 2-lane roads -- if you can introduce a bike lane, bus lane, or both, those methods of transportation become significantly faster, safer, and better. Biking is basically a non-starter without lanes; busses can be so slow as to be not worth using when they get stuck in normal traffic. The same argument applies to parking removal -- instead of using an entire effective lane of traffic for parked cars, we can dedicate it to bikes or buses.

Lowering the speed limit reduces noise at street level, makes streets safer to cross for pedestrians, and allows bikes to peacefully coexist with cars in an environment where you don't need to go that fast anyway.

It would be interesting to hear what holds you back from using buses, walking, or bikes instead of your car to get around town. In Denver, the main issues I encounter are:

- bike theft

- literal crazy people shouting at me on buses/trains

- drivers who park/stop in crosswalks, or try to kill me on my bicycle

- the bus network is extremely slow to get around town

I think there's a fair argument that we should focus on solving these problems first, before we degrade car traffic. Bike theft is a really bike one in Seattle, too, iirc, and a huge blocker for folks trying to switch away from cars. But eventually you need to degrade car traffic to make public transit as good as it can be.

[JPKab]

I live just south of Superior outside of Denver. I lived in DC area for 10 years. For 6 of those years, I commuted on the bus to metro to work.

The DC metro deteriorated markedly, and has continued to. A lot of it is a combination of bad initial designs (lack of surplus tunnel capacity to ease maintenance) along with the aggressive, powerful, and corrupt WMATA employees union. (I was on a project to analyze WMATA's staffing issues, and within the first hour, my team identified that there was a huge incentive to understaff the maintenance/technician teams to allow existing employees to collect massive amounts of overtime. Many would simply hide and sleep during the time they claimed to be "working". Hiring more mechanics/techs was foot-dragged, because it reduced the overtime pay for the existing workers who would interview them.). 2 mechanics working normal hours cost the same as 1 mechanic pulling tons of overtime, but the gap in productivity is huge. The WMATA union doesn't care. The rudeness of the staff is pretty legendary amongst locals as well.

Anyway, all of that is a long winded and detailed way of saying that WMATA gradually became a significantly less reliable means of transportation. My brother was on a car that got stuck in a tunnel that started filling with smoke. He stopped riding. And the buses need the metro to be running well. Without that, the buses become far less reliable. It's a shit show. And it's deteriorated markedly since I last lived there.

[dont__panic]

Hope you're OK after the Marshall Fire -- "just south of Superior" sounds like a very, very good choice compared to "in Superior" these days.

Do you use public transit in the Denver area at all? I find myself biking to most places because the public transit routes don't really get me where I want to go, but a lot of folks I know in the area used to use the buses and light rail in the before times. Seems like it had a pretty good rep before covid.

[JPKab]

Yep, it was spooky. Between my house and the fire was nothing but an open expanse of tall grass prairie and route 128. Had a clear view of the fires, especially at night. We were under pre-evac orders in case the wind shifted. I had a few former colleagues who lost homes. I'm grateful that the loss of life was as low as it was.

Regarding public transit in Denver, I avoid it like the plague. If I'm by myself, I'm a lot more tolerant of it. But I can't take my kids to public places in downtown Denver anymore, including the transit. When my daughter was 4, I had her on my shoulders on Mother's Day while we walked the 16th Street Mall. As we approached the Capitol, a violent altercation occurred within 30 feet of between two chronic drug addicts. One of them had a hiking pole, and he started beating and stabbing the other one. My daughter was terrified. That's just one incident, there are far more like it.

It blows my mind how the current crop of homeless (unhoused, or whatever moronically Orweillian term has been created to signal pious, virtuous sensitivity to ingroup members) activists have pushed the utterly failed policies of San Francisco in other cities. They result is what you and I are complaining about: public spaces that are decidedly unwelcoming and unsafe to children, elderly, and women. The policies seem to do nothing but funnel money to the non-profits that employ the nutbag activists. They certainly don't accomplish anything else. It's the equivalent of the neighborhood cat lady who puts bowls of food out for strays claiming she's a wildlife rehabilitation specialist.

[ThrustVectoring]

Speed limits are far less important than the psychological design of the road - any given section will communicate what hazards are more or less likely, and drivers are very responsive to these cues.

As a concrete example, I grew up near Seattle and regularly drove on East Lake Sammamish Parkway. This road was built and designed to efficiently carry traffic between Redmond and Issaquah at a speed of 45 miles per hour. It has smooth gentle curves, good sightlines, few driveways and intersections, etc. Sometime in the 90s or 00s people built a ton of really expensive lakefront houses between the parkway and the lake, and the new homeowners got the city to lower the speed limit to 35 (presumably to make it easier to get onto the road)

People generally drive 45 on it anyways. It is a road that practically screams "45 mph is safe" at you, and 35 feels downright glacial. If you lowered the limit to 25 people would probably still regularly do 40 on it - you need some kind of traffic calming as park of a major overhaul of the road to get speeds that are safe for pedestrians there. (And even if you could do this, most households in Sammamish travel to or through either Redmond or Issaquah anyhow, so they need some thoroughfare to do so - at best you're overloading and overstressing the other roads in the network)

[dont__panic]

Oh, totally agreed. Denver commits this sin all over the place, too. Honestly, the only place in the US that doesn't commit this is Boston and some parts of New England... because the roads were designed for horses at 10mph max and pedestrians.

[azylman]

> Here in city (Seattle) most people drive because transit tends to be spotty and slow for most people...So, what's the solution? Make driving worse of course. Speedbumps everywhere. Change 4-lane roads to 2-lanes. Remove parking. Lower speed limits to absurd levels. Make through streets dead ends.

This is obviously not the solution that anyone is proposing. You're arguing in bad faith against a strawman. The solution to bad public transit is to make public transit better.

[smegsicle]

You mentioned that induced demand is bad; someone pointed out that induced demand is not bad, but actually evidence of increased efficiency; someone else elaborated that the contrapositive is equally insane- if induced demand through efficiency is bad, then reduced demand through inefficiency is good- along with an example of the implementation of what you are asserting noone is proposing.

Caution against the short-sighted pursuit of easily-quantifiable goals at the expense of actual value is not 'arguing in bad faith'.

[ufmace]

How is he arguing against a strawman? He's saying that's exactly what they actually did in his city.

[azylman]

> Here in city (Seattle) most people drive because transit tends to be spotty and slow for most people...So, what's the solution? Make driving worse of course. Speedbumps everywhere...Transit still mostly sucks, but now driving sucks too...the transit folks realized it's hard to compete with driving, so they've just given up entirely on making transit great. It's easier to ruin driving.

The claim was that they put up speed bumps (and other measures) _with the intent of_ making driving worse to encourage public transit. That's obviously false. Speed bumps get put up to discourage unsafe driving.

If, when forced to drive safely, people would rather take public transit, that's kind of scary, but also a good thing I guess to get unsafe drivers off the road? However, that's not what the claim was (and in reality is unlikely to be true, though I have no data to back that up).

[onecommentman]

Not precisely to discourage unsafe driving. Simply to slow vehicles for any one of several reasons, safety often being an important one. Traffic calming has other benefits, such as more livable residential neighborhoods, and less congested residential side streets, especially during rush hours.

That does have the result of increasing trip times by cars, and thus motivating use of public transit.

Guessing intent is a fool’s game, and can’t really be true or false per se. It does antagonize automobile drivers and, from their valid but particular perspective, makes their life worse in (what would seem to them) a gratuitous fashion. Americans don’t like arbitrary and capricious as a whole.

[asdff]

Go to /r/urbanplanning and you will find this creed of road dieting written in stone tablets by a thundering voice

[kaesar14]

> I love transit and want more of it, but the transit folks realized it's hard to compete with driving, so they've just given up entirely on making transit great. It's easier to ruin driving.

It's way more like the driving folks have absolutely ruined transit in almost every single city in the country.

[kmeisthax]

You can't make transit great if cars are also great, because the two are mutually exclusive.

For cars to be good you need lots of space for parking lots and highways. Otherwise, the car is getting you nowhere fast, and there won't be anywhere to park it when you get there. But that also means those parking lots and highways need space. In all but the densest urban metros, that space is two-dimensional, which means all that car infrastructure is spreading out all the buildings.

Transit needs the exact opposite to happen: buildings need to be close-together so that a single line can aggregate more demand, and riders have to walk less when they arrive at their destinations. This is actually how pretty much all cities used to be built, because cars didn't exist yet, so you had to give that space to pedestrian infrastructure. Not coincidentally, those are also the cities with the best transit, and the absolute worst to drive in. You can't have both cars and people sharing the same space.

[throwaway0a5e]

> You can't make transit great if cars are also great, because the two are mutually exclusive.

I disagree. Regardless of your preferred mode of transit, look at the hours just before and after peak. Roads flow smoothly. Trains run at tight intervals and aren't too crowded. It's great for everyone.

Peak demand time will always be a clusterfuck but with enough infrastructure (ignoring petty ideological bickering about which mode should have what market share) we can probably have a system that's pretty damn decent the other 22hr of the day.

[zip1234]

You realize speed bumps are not there to 'ruin driving'--they are mechanical means to stop drivers from speeding as signs are useless and as soon as people are past the cops they speed again.

[Noumenon72]

Let's say they're put there even though they ruin driving for regular people, because they will also stop the few speeders. I don't really speed, but I take a speed bump as a sign someone in the neighborhood is hostile to drivers.

[AnimalMuppet]

I lived in this neighborhood, on a dead-end street. They grew a new subdivision, and put the street through. Now we had people blowing through our neighborhood at non-neighborhood-driving speeds, trying to race between major roads faster than the major roads would take them.

We petitioned to put speed bumps in. Yes, we were hostile to the way at least some people were driving. But also note that we, the people who asked for the bumps, also drove there every day. We weren't hostile to drivers as a class. We were hostile to people trying to drive excessive speeds on suburban side streets.

[alistairSH]

Almost nobody would disagree that making both transit and driving awful is not a good solution.

The real solution is to make transit at least as good as driving (measured roughly by time to get from A-B). Not easy to do in some cities - Seattle has some unique geography to work around. But for someplace like Houston or Dallas? Making transit work shouldn't be that hard (other than the cost to build it out and getting people to agree it can work).

[VintageCool]

> I love transit and want more of it, but the transit folks realized it's hard to compete with driving, so they've just given up entirely on making transit great. It's easier to ruin driving.

Seattle just opened light rail from Northgate to the U-District to Downtown this year. We will also have light rail from Downtown Seattle to Bellevue opening next year, and light rail to Redmond the year after that.

And the opening of light rail from Downtown to Capitol Hill to Husky Stadium a few years ago drove some pretty big changes in transit in Seattle.

[robcohen]

> I love transit and want more of it, but the transit folks realized it's hard to compete with driving, so they've just given up entirely on making transit great. It's easier to ruin driving.

Wow. You just crystalized exactly what I felt was wrong with the argument that induced demand is bad. Thanks.

[crowbahr]

It's an entirely bad faith and shallow argument. You should probably reconsider what you're thinking is.

The goal of transit first infrastructure is to make the majority of trips unnecessary. You shouldn't be required to own a car to participate in American society.

This means we need to rezone our residential sprawl to allow for more frequent, smaller grocery stores. We need to increase the amount of mixed zoning, increase density, decrease the insane quantity of land dedicated solely to the movement and storage of privately owned heavy machinery (automobiles) and focus on easily accessible areas of bike & bus friendly infrastructure.

The Netherlands was fully capable of transitioning from a nation of car dependent choked cities to a bike first micromobility haven in 30 years. The only thing stopping the USA from doing the same is the enormous government subsidies paid to car owners to keep the roads paved.

If the federal government stopped taking 90% of the cost of every road in the US and you had to pay gas tax to support it all do you think you'd still be driving? Do you think you'd support billion dollar bridge extensions and lane additions when it means gas is an extra $5/gallon?

[twoodfin]

If the federal government stopped taking 90% of the cost of every road in the US and you had to pay gas tax to support it all do you think you'd still be driving? Do you think you'd support billion dollar bridge extensions and lane additions when it means gas is an extra $5/gallon?

The Federal Highway Trust Fund was fully funded by the gas tax and other user fees until 2008, all while a significant percentage of revenue was allocated not to roads but to mass transit. Congress has topped it up with general revenue since, but the gas tax hike required to eliminate that need would be measured in cents, not dollars.

[pbourke]

> The Netherlands was fully capable of transitioning from a nation of car dependent choked cities to a bike first micromobility haven in 30 years. The only thing stopping the USA from doing the same is the enormous government subsidies paid to car owners to keep the roads paved.

The Netherlands is smaller than New Jersey and has twice its population - its one of the most densely populated countries. Comparing it to the 3rd largest country on earth is risible.

[crowbahr]

The Netherlands cities are significantly smaller than American cities in terms of population.

NYC doesn't even have good bike infrastructure.

Every major city in America could transition to bike infrastructure and the quality of life would improve across the US. We don't have to cross the great plains on a bike: We're talking micromobility here. Who cares if they're smaller? We have enormous cities choked to death with cars.

Death to cars: cars bring death. Cities are for humans, not cars.

[seanmcdirmid]

> Here in city (Seattle) most people drive because transit tends to be spotty and slow for most people.

I don't drive and I live in Ballard. Driving has always sucked in Seattle since I can remember from the late 1970s. My dad, who lived in Seattle after coming back from Vietnam said the same thing.

[mikestew]

Transit still mostly sucks, but now driving sucks too.

And now bicycling and walking suck just a little less. That is a success.

[potta_coffee]

I've always hated driving around Seattle, but a few years ago I was bumming around for a few days in my Miata and it was a whole different experience. Having a tiny car that can go anywhere and park anywhere is awesome.

[bobthepanda]

The speeds were not reduced because the transit needed to put more people in.

The speeds were reduced because people keep dying when getting hit by speeding cars. And this problem has gotten worse with Americans shifting to SUVs and crossovers that hit humans higher up and toss them under the wheels.

[animal_spirits]

The less you invest in public transportation, the more people will drive. The more people that drive, the slower traffic gets. If you just widen the road, all you do is increase the amount of cars that drive. If people can't get to where they are going via public transportation, then they are going to drive instead, increasing congestion. Would recommend watching this video on it:

https://youtu.be/RQY6WGOoYis

[criddell]

I think generally what you said is true, but there are other factors. Right now we're in the middle of a pandemic. I'm very thankful I don't have to rely on public transportation.

[massysett]

Yes, if you increase the amount of road and more cars get people to where they are going, the result is increased economic activity. The result also is increased well-being because more people are getting to places where they wish to go - destinations that are improving their lives. This is a success.

[animal_spirits]

You actually see the opposite. Close nit places with more foot traffic and better public transport see higher economic activity and financial resilience. Places with long roads between where people live and where they shop/work/eat _drastically_ harms financial productivity due to higher infrastructure costs. Chuck Mahron makes this point in his TEDx talk. The infrastructure _maintenance_ costs of sprawl dramatically outweighs what a city makes in revenue from taxes they receive.

https://www.youtube.com/watch?v=JPbfdcvv0to

[mjmahone17]

Road usage isn’t necessarily success. For a political region, economic activity is usually considered a success.

If by building a larger road through your city, you induce people to live outside of your city instead of in it, then you’ve added costs while reducing your economic activity, while creating more total wasted hours in traffic in the process.

Are the trade offs worth it? Sometimes! But induced traffic demand is not by itself a success criteria for regions: it’s only a success if it means more people are able to work and have higher productivity in a region, as opposed to just spreading out the existing workers and reducing their productivity through increased commute times.

[twoodfin]

I’m not sure that tracks: If a new road allows me to build a home where I would not have built a home before, that’s economic activity enabled by the new road.

[alistairSH]

But it's activity somewhere other than where part of the road was built.

Take DC and NoVA, typical large suburb next to a large city. If DC wants to increase economic activity, does it want to invest in a new bridge that allows more people to live in NoVA (where most of their retail/commercial activity will occur)? Or, would DC be better off spending that money on redeveloping run-down neighborhoods and adding some light rail (or other transit improvements)?

[kevinmchugh]

Doesn't DC have a height limit on buildings? Seems like eliminating that would be a way for the city to increase economic activity without spending any money

[alistairSH]

Yes, that’s a fairly unique rule. IIRC to protect the aesthetics of the downtown monument/lawn zone (which includes the WH and Capitol). Arlington across the river has all the tall office buildings.

But I have no idea how much DC “needs” the vertical space for development. It isn’t nearly as dense as NYC - plenty of infill (re)development to be done, I would guess.

[massysett]

The workers have spread out because they prefer spread-out housing. They prefer larger homes on larger lots. Roads allow people to live where they wish in the housing they want. People are willing to accept longer commutes so they have the housing they want. This is a success.

[VintageCool]

Expanding highways is sold as "making traffic better", or "scaling to day-to-day traffic" as the grandparent poster put it.

However, what expanding highways actually accomplishes is incentivizing people to move out of the city because they can have a commute which is longer in miles but shorter in minutes. That lasts until enough people move to the suburb that the commute is now longer in miles AND equal time or longer in minutes. You haven't made traffic any better, you've just made sprawl worse and you've increased the vehicle miles traveled to accomplish the same result of getting people where they want to be.

The message of the New Urbanists is that we should make our cities more livable and build/allow more housing units within the cities so that more people can live where their commutes are short (in terms of miles) and the increase in density will make providing transit more cost-effective.

[NikolaeVarius]

If the point of adding lanes is to reduce delays, and induced demand prevents that, you have failed in the task.

[dragontamer]

The point of roads, from the city's perspective, is to support additional transportation, which causes growth of the city.

More transportation means more trade, more services, and better life for all who live near the roads. It might be in the form of easier-to-get deliveries (Amazon goods), or new jobs that have popped up close by, or new housing developments (aka: homes that previously weren't possible due to the time of transportation, but are now possible thanks to sped up transportation times).

-----

It turns out that "individualism" is a crappy reason to do anything. The individual argument must be made because we live in a democracy, and its impossible to get the people to agree to something unless you sell them a story regarding individualism.

[NikolaeVarius]

You are moving the goalpost.

The purpose of adding lanes was to REDUCE DELAYS. Not support additional transportation. Your entire post hinges on an incorrect premise

[azylman]

It's not correct that cities look at road throughput with no concern for how long that travel takes. The success criteria that city planners use always includes travel times which are impacted substantially by traffic congestion.

[bluGill]

That means you didn't add enough lanes. You need to get ahead of induced demand, otherwise you city isn't meeting the needs of the people who live there. If you don't want to have many places you can reach in a reasonable amount of time can you can move to a rural area. The point of cities is to give people options to reach lots of places quickly. Get busying being a good city.

Note, it can be better to add transit other than lanes of road. Even though I said add lanes, adding lanes is but one possible solution. Good transit may well be better. Figure out how to make your city serve the people who want to get around.

[dragontamer]

> You need to get ahead of induced demand, otherwise you city isn't meeting the needs of the people who live there.

Well, there's an annoying edge case that must be considered as well. In some cases, "induced demand" is "stealing demand from somewhere else".

Lets say you have Town Foo and Town Bar. If you build a highway to Foo, all the additional traffic might be "stealing" traffic from Town Bar and benefiting Town Foo. Especially if people emigrate out of Town Bar for closer housing to Town Foo, you didn't really improve the lives of anyone. You just caused everyone to migrate over.

---------

Ideally, you want to build highways / roads / transportation in ways that benefits people, and causes the least inconvenience to other towns.

[bluGill]

Only if town bar isn't a place people want to be. I call it a good thing is bad towns die.

[NikolaeVarius]

Well sadly, roads have a bad habit of being confined by physical time and space and cannot just be arbitrarily widened.

[bluGill]

You can go up and down though.

Again, I'm not making a value judgement here. Transit is a valid option that could be better

[ryukafalz]

Up is expensive and rather unpleasant for those walking nearby on the surface. Down is even more expensive.

Don't forget that no matter how many lanes you add to a highway heading into a city, eventually that highway ends up... in the city. Too many cars in a city makes for a loud and dangerous-to-navigate environment for those who live there.

[asdff]

The point of adding lanes is not to improve commutes. It's to improve thoroughput. If you add more lanes, and traffic moves at the exact same speed as it did before, guess what that's a win. Your throughput is now higher, more vehicles are moving per hour, and that ultimately means fewer trucks clogging up the port across town (or across the country).

[rootusrootus]

If induced demand is going to negate the improvements from adding capacity, then why not just reduce capacity to one lane? Or less?

[nostromo]

The point of adding lanes is to increase throughput.

[zip1234]

If driving demand can be induced by massively subsidizing it with billions as is currently done, so can other forms of transportation.

[Spooky23]

The problem is that demand has other consequences.

I drive 2-3 times a year from NY to South Carolina or Florida for years, always timing crossing through DC around 5AM. Traffic 15-20 years ago coming into DC extended down to Potomac Mills. When I passed though in 2019 it extended almost 60 miles, well past Fredericksburg!

More demand drives more sprawl that drives more demand for roads. Eventually metastasizes into a nightmare like LA or Long Island!

[IdoRA]

Part of the reason there is unusually high traffic in that location is the confluence of two things: one is that local traffic doesn’t have a great alternative to 95 over the Rappahannock river (the local Rt. 17/1 interchange is famously awful) so you take 95, and the other is that there is a large amount of truck traffic between Rt. 17 and 95. Basically over the span of the Stafford/F’burg area 95 sees an additional ~30k cars/day. There are road improvements in progress but they are too little, too late.

[azylman]

It depends what your success criteria is. It's true, you've successfully increased the throughput of the transit network, but you haven't done anything to improve transit times - you just have more people stuck in traffic now. There are other ways you could have spent that same amount of money (public transit) that both increase the throughput of the network _and_ improve transit times.

[mrfusion]

But those extra people are choosing to be there so there must be some benefit.

[tshaddox]

They're choosing to be there now, precisely like they were choosing to not be there before you changed the roads. Other people are also choosing to not be there, and instead choosing to live in the woods in northern Canada. I'm not sure how this mode of argument is really demonstrating anything. It seems like you just considering literally any state of affairs other than active physical coercion to be a good state of affairs.

[seanmcdirmid]

> But those extra people are choosing to be there so there must be some benefit.

As long as your roads are saturated, they have less throughput, not more. It is kind of like a clog in your toilet: more things are there in your pipes, but not much is getting through.

[throwaway0a5e]

A clogged toilet isn't flowing. More like dumping a 5-gal bucket into a sink . The drain is running at full capacity but any one drop may take a long time to actually clear the sink. The 5-gal bucket is peak demand. Total time to sink clear is how long rush "hour" lasts.

Fluid analogies are crappy because fluids flow more when you add pressure and traffic doesn't.

[seanmcdirmid]

> because fluids flow more when you add pressure and traffic doesn't.

Well, traffic can flow when pressure is added, just not in a way that is very safe.

[jimmaswell]

If your city sewer is clogged, so you widen it, then more people install toilets in their houses and bring the sewer back to capacity, I think that's still a win.

[njarboe]

Not if you build enough roads. This argument just does not hold up. There was less time wasted stuck in traffic in the past. Go with tunnels underground so as not the create the large problems with having surface roads. If your idea theory is right, why don't we just stop maintaining all roads, shut them down, and save a lot of money, if new roads are useless.

[tshaddox]

In some cases it might be theoretically possible to just outspend the problem. But in most cases the roads have to be going somewhere, and you don't have significant control over where and how big that somewhere is (i.e. you can't easily move a whole urban center, or slice it into chunks and move all the chunks apart from each other a little to fit more roads). If all the roads are ending at the same place, making wider and longer roads to that place will (often) just induce more people to drive to that place from further away.

The reason "just shutting down all roads" doesn't make sense is that it doesn't solve the actual problem, which is that people want to both work in places with good jobs (traditionally often dense urban centers) while living in cheaper places that are far away and not spend significant chunks of their lives stuck in traffic. Shutting down all the roads only "solves" the traffic problem in a deliberately ridiculous sense (same as "just kill all humans").

[Spooky23]

Shutting down or tolling chokepoints lowers the opportunity cost of alternatives.

I work for a big central business district employer. You can pay $150-250 a month to park or $75/week to take a motor coach bus from your suburban town. Those numbers drive behavior, and make for a better solution as folks who need flexibility can pay for it.

[jimmytidey]

Fascinating that this has generated so many answers, from so many different perspectives.

Induced demand is a terrible name for the real issue here. Perhaps the "one more lane fallacy" would be better. The "one more lane fallacy" is not universal, it only applies in cities and other densely populated areas.

Imagine you are sitting in a suburban traffic jam, getting slowly more and more annoyed. It's easy to imagine adding marginally more road capacity would put an end to traffic jam. That thought is the 'one more lane fallacy'. That, admittedly attractive, idea is wrong because adding more capacity leaves the traffic jam exactly the same, with more lanes and more cars in them - because of induced demand.

The kicker is that in a densely populated area, there is often no realistic prospect of adding enough road capacity to end traffic jams, simply because of there is not enough space. I suspect that in most cases, road building achieves political support through the expectation of ending traffic jams. Nearly always, this expectation will not be met. This is the essence of the induced demand problem - it is not as obvious as is sometimes made out.

So, even if you are die hard driver, if you want to reduce traffic jams, you should advocate for other people to use transport methods that are more space efficient than driving. Of course, you might want to live in an area dominated by constantly congested roads, in which case, induced demand isn't a problem.

[benf76]

So why bother build any roads larger than one lane?

[jimmytidey]

You need some road capacity for ambulances and Deliveroo.

[JPKab]

Just to be clear (I lived in DC/northern Virginia for 10 years, and witnessed induced demand over and over), if the goal of widening a highway is to ease traffic congestion, induced demand quickly makes this a failed strategy. In northern Virginia, every project to widen 66 or 95 has always been sold to taxpayers as a move to ease congestion. But the result of that is temporary. As soon as the congestion is eased, cheapish land opens up for new development and more affordable housing. People flock to these new developments, and the cycle repeats.

It does result in growth for an area, but quality of life stagnates. The traffic in northern Virginia/DC/Maryland is at a point where it noticeably affects the mood of a bulk of the people who live there. Spending 90 minutes each way day after day after day fucks people's heads up.

[kmeisthax]

90 minute commutes not only fuck with people's heads, it also creates Stockholm syndrome where people start talking about how cars are freedom. This isn't directly caused by the commutes. It's more that car-dependent suburbs also can't support transit infrastructure, so not having a car at all is still worse than 90 minutes of lost time.

[ThrustVectoring]

Taking a trip is a cost, not a benefit. It's evidence that the cost of the trip is considered worth taking and that there's some advantage being gained, but more trips in and of itself is a terrible metric.

[tshaddox]

In some sense I understand what you're saying, but that mode of argument has limitations. Like, you certainly wouldn't say "I don't understand how increasing medical costs doesn't count as success, that means people want to spend their money on medical care, doesn't it?"

[twoodfin]

If you doubled the number of hospital beds, doctors, nurses, diagnostic equipment, labs … and demand was high enough to keep prices constant, you’ve doubled healthcare access at a rate patients were already willing to pay.

“Induced demand” in every other industry is described as “latent demand”.

[sagarm]

Induced demand actually does happen in American healthcare: spending goes up with healthcare availability, but health outcomes do not improve past a fairly low level of usage. This is a waste, not productive economic activity.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8057171/

The situation with roads is not that different: building more road capacity incentivizes sprawl, leaving the entire network more congested than it was when you started.

Roads just don't scale. The daily commute is like a distributed shuffle: time to complete the shuffle scales superlinearly, probably quadratically given the limited topologies possible with roads. It's not like you can build a hypercube road network.

[tshaddox]

No one is against increasing access to healthcare. But I deliberately chose the example of healthcare costs to be analogous with people experiencing traffic congestion.

[twoodfin]

Right, and I’m suggesting they are, in fact, quite analogous in this context. If there’s latent, unsatisfied demand for healthcare, and you increase the supply, you shouldn’t be surprised or disappointed if the new supply is consumed. More people are getting the healthcare they wanted!

[tshaddox]

Yes, but people aren’t complaining that more people drove the route. They’re complaining that congestion was not reduced. And congestion is bad.

[shkkmo]

> I've never understood how inducing demand doesn't count as success.

That depends on what you see as the goal. If the goal is reducing congestion, then induced demand means that particular goal is harder to achieve. If the goal is to get more people driving then induced demand is a clear success.

[tshaddox]

Why in the world would "get more people driving" be a measure of success? For industries that directly benefit from that, sure, but I can't imagine how that could be a societal goal.

[dragontamer]

Transportation is directly related to how much your local cities are doing.

When you order goods from Amazon, that gets delivered to you. It might be a road, sea, rail, or plane, but its transportation. The more of packages ordered / delivered, the more things are happening in the city.

The more jobs being created, the more people will need to transport to-and-from work. The more homes built, the more transportation is needed. Etc. etc.

Its a crude measurement with flaws, but generally speaking, the more transportation that's happening, the bigger and better the city is functioning. People wouldn't travel unless they needed to (travel always sucks: traffic accidents, getting stuck, dealing with others on planes/trains/busses, etc. etc.). But we deal with it because without transit, we couldn't do our daily business.

Be it a meeting for work, going to school, delivering goods or other such need.

-------

Mass transit options, like Rail, get more things done with far less money. But there's a latency issue: rail can be slower for the individual... but its cheaper and more-bandwidth for the city.

This conflicts with individual options like roads: it costs a gross amount of money for an individual to buy a car / use it on the highways (plus the cost of highways themselves: rubber tires wear out faster than steel wheels on trains. Asphalt roads need replacing more often than steel rail lines. Gasoline costs much more than the electricity used to move a train). But the individual latency is such an advantage, that the individual will typically prefer car travel.

[tshaddox]

Yes, but if you reduced the average amount of time stuck in traffic while the total number and distance of trips remained the same, you certainly wouldn't say that your local city is doing worse. Moreover, if you replaced some car trips with other ways of transporting the same person or freight, that certainly isn't a loss for your local city simply because the number of people driving decreased.

[kmeisthax]

Cars don't have an individual latency advantage. If you want to travel somewhere during rush hour, you still have an hour of latency, even if the trip would ordinarily be 15 minutes.

What they do have an advantage on is not having to synchronize with a schedule. If you need to travel 15 minutes by light rail, but the train only comes around once an hour, then missing the train adds an hour to your trip. It doesn't matter if the train never breaks down and has separated right-of-way - running on time is useless if you're not.

The way you work around that is by running more trains so that they can come more frequently. My rule of thumb is that if a transit line has a frequency of 15 minutes or less, I don't need to worry about the schedule because the time spent waiting for the train or bus is less than the time of the overall trip.

However, this is expensive; it only makes economic sense if you actually have that many riders that need to travel along that line. In other words, demand needs to be aggregated. The problem is that cars work the opposite way: they exist specifically to segregate demand. This occurs both directly and indirectly. The direct effect is the ability to immediately depart, which I already mentioned; but the indirect effect is the result of all the infrastructure that cars need in order to work at all. Things like wide highways and parking lots spread out where people need to go and make it far more dangerous to walk from a train or bus stop to your final destination.

In other words, cars cheat - they don't make your commute better, they make anyone who does not own a car have a worse one.

[asdff]

Freeways also carry significant trucking traffic. Like iPhones and food? Increasing throughput makes these things cheaper to deliver into your home from where they are produced.

[mrfusion]

But more people wouldn’t drive if there wasn’t a benefit to it. So you’re benefiting more people.

[kaesar14]

Because the metric people care about is traffic on the roads, not how many motorists are able to use the road in a given day. The Big Dig by this metric was a resounding success in Boston, able to dramatically scale up the amount of commuters in and out of the city, but driving still absolutely sucks because of traffic. To the person on the road, the Big Dig solved nothing.

Parent comment is saying the only way to scale with higher demand of transportation in a way that feels like an actual improvement to people is public transit, because public transit scales so much better with higher numbers of people commuting.

[whatshisface]

If the metric was really traffic, then that could easily be solved on any road by only allowing even-numbered license numbers to drive on even-numbered days, and vice-versa. If that's an absurd solution, then traffic severity is not the only metric.

[seanmcdirmid]

> If the metric was really traffic, then that could easily be solved on any road by only allowing even-numbered license numbers to drive on even-numbered days, and vice-versa.

They tried this in Beijing. People would just buy second cars so they could drive on both days. Eventually they had to restrict new license plates as well.

[tshaddox]

I don't think anyone is claiming that is literally the only metric, because if it were, you could also just ban driving completely, or kill a bunch of people, etc.

[kaesar14]

I mean, I don't see how that's really a fair response to saying what people care about is traffic. Yeah, ability to use the road, sure. I don't think people want a new highway to be built and then told they can't use it because they don't have a new car or something.

I as a motorist could not give less of a shit if I'm stuck in traffic for 3 hours a day but the road is able to move hundreds of thousands of cars a day. I'd prefer a road that could only move 20 people a day with 0 traffic. It's the only thing I care about.

[bagacrap]

why would you count that as a win? you almost certainly wouldn't be one of those 20 people allowed on the road

[kaesar14]

The example was clearly intended to include the motorist in question, being allowed to be on the road. As long as the motorist got to use the road, it wouldn't matter to said motorist how large the capacity of the road was, if they weren't able to clear through it quickly without traffic. It wouldn't matter if the road in question was servicing large amounts of people, it's only visible impact to the motorists time on the road that matters.

[sokoloff]

Having lived through it all and seeing the outcome, the Big Dig was a pain while it was happening, but a smashing success now that it’s done. A later removal of some of the toll booths in favor of automated tolling has made the road network even more effective.

Is there still some traffic? Yes. Is it better than it was 30 years ago, even as the roads handle way more traffic? Absolutely.

[kaesar14]

I'd rather the T be functional and get me to where I need to be, and a better commuter rail system, then having to drive to and fro on Storrow at rush hour. There's no amount of bridges or expansions to the roads that would make it better short of leveling the city to build a giant highway, which I'm sure some percentage of Massachusetts drivers would be in favor of.

[sokoloff]

You prefer the T or commuter rail. That's fine and improving those modes of transit seems a fine goal as well. That preference/goal doesn't support an argument that the Big Dig solved nothing for those who choose to drive.

[kaesar14]

The only goal is to get in and out of Boston in a reasonable amount of time. I wasn't around for pre Big Dig Boston but it's still dangerous and time-consuming driving to get out of Boston by car. The Big Dig might've made it _less_ dangerous and time-consuming, but the point is the solution barely scales since the total number of people driving just increased instead. If they spent those 20 years and billions of dollars on burying and expanding the T lines, and improving the commuter rail offerings, I wager we'd have achieved a lot more towards the aforementioned goal of getting in and out of Boston quickly.

[imgabe]

The goal of building new roads is to decrease congestion and reduce travel times.

If you build a new road and it gets just as congested and it takes just as long to travel from A to B, then what did you accomplish?

The number of people who want to use a road is not the metric we're trying to optimize here. If we wanted to do that we should build as few roads as possible. Then there would be tons and tons of people who want to use each road. Hooray! Success!

[bsder]

> I've never understood how inducing demand doesn't count as success.

More lanes generally improves throughput. However, more lanes often increases latency.

City planners may prefer this, but individuals may not.

[megablast]

It is. If you work for an oil company. Or love pollution. Or hate the planet. Getting more people driving is awesome!!

[mrfusion]

You’re spot on. Plus the argument doesn’t hold water since there are a finite number of potential drivers.

[asoneth]

"Induced demand" doesn't just mean increasing the number of drivers, it means increasing the number of miles driven.

In a metro area housing prices are generally correlated with how many minutes it takes to get to a city center. If you add highway capacity then people will choose to move further out to the suburbs. (Though that is great for property values, especially around the periphery of the commuting range.)

[rayiner]

I grew up in Northern VA. Public transit here is a solution looking for a problem. The job centers and commercial are too spread out for public transit to make any sense. Most of the population and jobs in the DC metro area aren’t in DC but spread around in Tysons, Loudoun, Reston, Arlington, Bethesda, etc. The state spent billions building the Silver line out to Tysons, Reston, and Loudoun, and ridership was disappointing even before COVID. (And it’s approximately zero now.) In a traditional hub-and-spoke city like Chicago, heavy rail can bring tons of commuters down to where the jobs are in the core. But when the jobs are spread out all over the spokes, that model breaks down. It’s impossible to take Metro to Reston from most of the surrounding residential areas (all the ones except the narrow slice on the Silver line itself). And it’s a huge pain in the ass to do the spoke-hub-spoke commute and take Metro from a different suburb to Reston. And for married couples, it’s a real roll of the dice whether both your jobs will be easily accessible via Metro.

Rail transit is an anachronism, best suited for the 1950s when life involved a woman staying home with the kids while dad took the train into the city for work. I did that for a year before my wife started her job and it was lovely (took Metro North down from Westchester to Manhattan every day). But in a modern family with two jobs in two locations, plus kids with daycare and school and after school activities, it’s not scalable.

My wife and I are “city people.” We really tried to scale the transit lifestyle. We lived in downtown Baltimore for two years and took Amtrak to work each day. We lived in downtown DC and took Metro. We’ve commutes in the Silver line, Orange line, Blue line, MARC, etc. And every year the service got worse, and every time we had another kid the equation got harder to balance. Eventually we threw in the towel, moved to a red county, and bought an SUV that gets 13 mpg. And we’ve never looked back.

You want to know what the future of America looks like? Go to the Dallas suburbs. That’s where all the immigrants with kids are, and where the next generation of Americans are being raised. It’s a glorious place. And it doesn’t involve public transit.

[seanmcdirmid]

> But when the jobs are spread out all over the spokes, that model breaks down.

So don't spread the jobs out all over the spokes? Is some urban planning really hard to do here?

> Rail transit is an anachronism, best suited for the 1950s when life involved a woman staying home with the kids while dad took the train into the city for work.

That isn't true at all in much of the world. Rail transit still works in many non-dysfunctional countries.

[mardifoufs]

Yes, it's hard to literally relocate hundreds of thousands of jobs according to some urban planners dreams. We aren't talking about intra city planning, but about state wide job markets. I guess Canada is dysfunctional too because there is absolutely no way to get rail service working beyond the big cities. Maybe it has something to do with north America not being Europe so trying to just force a European model here is a pure pipe dream.

Again, not talking about public transit in cities (which is amazing and should be scaled up) but about intercity/state/province transport. The distances, and spread are just not comparable to almost anywhere else in the world and you can't just magically make everyone move.

[kaesar14]

The context of this thread is about Virginia which is part of the I-95 corridor, the most densely populated area in the country, with a population density comparable to many Western European countries[1].

This is like the one region of the country you actually could scale up intercity/state transport, and it sucks so bad that Amtrak is terrible.

1: https://tetcoalition.org/wp-content/uploads/2015/03/2040_Vis....

[mardifoufs]

I guess it could be, but the point of the GP was that the jobs and the population were spread out widely even if the population density is similar. Now I could be wrong, but from what I know from the half of my family living in France, transit in Paris for example is mostly pouring into the city where the jobs are. In this case, everything is spread out, so the density itself does not really matter. The problem is the spread.

Even here in montreal, while the metro is pretty good and we are currently building a pretty nice light rail system you still can't really depend on the rail system if your job isn't in montreal itself. The whole transit system is based on feeding the big city, not move people in between smaller cities. (Also, It's a bit tiring then to hear about just how dysfunctional the US is and how good they have it everywhere else when it's just not true. The American self loathing just get repetitive honestly)

I think public transit is amazing for city transit but does not scale very well when there's something else than the usual suburb->city->suburb pattern of movement. You can't really interconnect every single medium-small ish city at a north American scale

[kaesar14]

You can connect those smaller cities with stuff besides rail, you know.

[seanmcdirmid]

> Again, not talking about public transit in cities (which is amazing and should be scaled up) but about intercity/state/province transport. The distances, and spread are just not comparable to almost anywhere else in the world and you can't just magically make everyone move.

This problem has been solved for awhile now, at least since the 1960s when the first intra-city/province shinkansen came online. Just because some other countries suck as badly as the USA at it doesn't mean it is an unsolved problem.

[mardifoufs]

There's just absolutely no way to compare the shinkansen to what would be required in the DC/VA area. Yes the US should connect its big cities with high speed rail but that would still not do anything for small intercity transit for everyone else

This is just rehashing pop-urban planning buzzwords. Like I'm not sure where the trend of just handwaving every problem as easily solvable by "rail! Shinkansen! City public transit even out of cities!" came from but it particularly does not make sense in this situation considering the commenter you replied to specified he talked about spread out, smaller cities with frequent stops. Which is the opposite of what the shinkansen is for.

[seanmcdirmid]

> Yes the US should connect its big cities with high speed rail but that would still not do anything for small intercity transit for everyone else

Have you ever tried taking these lines before? They have high speed rail between big cities, and tons and tons of small branch/feeder routes out to small towns with the most frequent stops ever imaginable. Getting from huge Tokyo to small Gifu actually works.

It did take some planning however. The USA's model of just "build that office complex wherever you want!" wouldn't work.

[rayiner]

> So don't spread the jobs out all over the spokes? Is some urban planning really hard to do here?

“Just completely restructure every single place 80% of the population in one of the country’s largest metro areas lives and works in.”

Yes, there is an argument that Reston, Vienna, etc., shouldn’t exist in their present form (or anything close to it). But that ship sailed long ago.

Efforts to gloss over that reality end badly. The Silver Line and all the adjacent development are monstrosities. Stations are huge concrete edifices in the middle of freeways that are nerve wracking to navigate with a squirrelly three year old. Billions were spent making places that are nice for just a handful of people who can afford $4,000/month for a two bedroom near the McLean Metro so they can take the Silver Line to their job at Google in Reston.

> That isn't true at all in much of the world. Rail transit still works in many non-dysfunctional countries.

Those countries are dysfunctional. Birth rates in these transit-oriented metro areas are well below replacement, meaning that their form of civilization is literally sustainable.

[asdff]

>So don't spread the jobs out all over the spokes? Is some urban planning really hard to do here?

Yes, impossible actually to prevent this from happening. Corporations always want a good deal for office space, so they will literally shop around different cities looking at who will give them the biggest tax advantages and the most developable land. City councilmembers literally make careers out of wooing corporations into building suburban office parks, and why wouldn't they? They just injected a thousand white collar workers who will be paying taxes into their school district and another 5 thousand workers who will be driving in every morning and spending money on local sales tax when they get starbucks from the drive through. It's a race to the bottom as long as local governments have local control over their planning processes, and it would probably still continue if planning were done regionally or nationally since it is very easy to bribe American politicians.

[flavius29663]

> Rail transit still works in many non-dysfunctional countries.

Define "works". Sure it can move millions of people each day, but those people live miserable lives most of the time. Have you lived in a city where commuting one hour each way by train is considered "very good" ? And some of the worse are around 1.30-1.45 hours each way, each day? Even if for a while the train is fine, if the city is growing it will become unbearably crowded, smelly, hot and just a nightmare to deal with when you're tired and want to get home at 6 PM.

[MandieD]

Yes, our life in Franconia (northern Bavaria) is nothing but suffering, in our townhouse with a yard that’s a 600m walk from a subway station and a suburban rail station, either of which gets me to downtown Nuremberg in 20 minutes, because that place is a hellhole, and to the miserable corporate 35-hour-a-week job (the fault of IG Metall) that pays for said townhouse in 40 minutes. I especially resent the fact that I can go out for that swill they call beer in Bavaria with my colleagues after work in that dump called downtown Nuremberg without worrying how I’ll get home.

A truly regrettable existence that no human should have to endure. We mourn the lack of a reason to own a second car. My husband’s bike ride to work is an even worse torture.

[flavius29663]

I was talking about cities (e.g. London) where commuting by train+buses takes 1-2 hours each way. Not sure why you thought I was talking about medium sized cities where you can drive anywhere in 20 minutes. Washington DC is just massive, the metro area is immense both area and population wise, public transport wouldn't do much there.

[selimthegrim]

To be fair, I have no idea how my cousin managed to afford a house in Wendelstein, they all seemed pretty expensive for being a drive away from the subway as opposed to a walk.

[KerrAvon]

Caltrain in the SF Bay peninsula is basically that and people do cope with it and manage to lead happy, fulfilling lives.

[gitgrump]

works - verb. Moves millions of people efficiently and without the pollution or danger of driving an expensive, private vehicle.

[btreecat]

>And every year the service got worse,

Because every year we refuse to fund public transport at an appropriate level to prevent it from getting worse let alone improving.

If your idea of public transport is confined to only what the US has to offer currently, then you have already stopped having a conversation in good faith and instead are being myopic in the realm of solutions.

[aidenn0]

I also grew up in Northern VA. Biggest issue there is how hard it is to build public transit. The silver-line was such a clusterfuck largely because of fights over who should pay[1], how much it should cost and how to balance construction-induced disruption and costs with long-term TCO.

If we could build rail miles as cheaply and quickly as Western Europe, everyone in Fairfax Co could commute via rail except perhaps those work west of there.

1: Fairfax county is rather centrally planned compared to everywhere else in the US I've lived since then, but the DC Metro is funded by MD, VA, DC, and the federal government. The difficulty of building infrastructure seems to scale super-linearly with the number of people paying for the infrastructure...

[rayiner]

> If we could build rail miles as cheaply and quickly as Western Europe, everyone in Fairfax Co could commute via rail except perhaps those work west of there.

I agree. But we can’t. It’s a cluster fuck even when it’s just one state. Maryland spent $7 billion building the Purple line, which is what Western European countries spent for similar amounts of fully automated underground heavy rail.

At some point we have to treat our infrastructure costs as realities to be planned around rather than solvable problems. This is a keen insight Lee Kuan Yew had in building Singapore. He admired many aspects of Anglo culture, but realized that not all of them would work in an Asian country: https://web.colby.edu/eas150/files/2017/11/Zakaria_LeeKuanYe.... America is a decentralized, low cohesion society built around having plenty of space for a bunch of different groups to leave each other alone. America is continually replenished by the people who are antisocial enough to leave their kin and homelands to start new lives thousands of miles away.[1] We aren’t Germans or Swedes or Japanese and shouldn’t beat our selves up trying to be them. Our future is electric cars and freeways, not trains.

[1] Asians are the biggest immigrant group in the US, but when polled, under 10% of people in Asia said they would immigrate to another country if they had the chance. Guess what kind of people end up making the journey?

[aidenn0]

> At some point we have to treat our infrastructure costs as realities to be planned around rather than solvable problems.

I think this is the main point of disagreement in this thread; if we have to spend $500M/mile for light rail in the US, it's fairly obvious that rail is not an option. If there is a large learning-factor for building rail that would bring costs down significantly with more miles built, then rail is certainly an option for the northeast US.

[rayiner]

Yes—I think it’s a difference between people who accept that light rail costs us $500 million/mile and subways cost us $5 billion/mile and those who don’t. Also, those who think we can run reliable, efficient public transit even with good funding, and those who accept that we can’t.

I used to be a rail fan. Then I rode Amtrak to work for a couple of years. I saw the DC Metro, which is well funded, so badly maintained that automated train control, a core feature when the system was built 1970s, had to be turned off. (That was a decade ago and there is no sign of it ever being reenabled.) I came to the conclusion that Americans running transit projects like the Europeans or Japanese is just wishful thinking. A camel cannot be a bird no matter how much it wants.

[btreecat]

>and those who accept that we can’t.

So prove it with more than your ridiculous anecdotes and metaphors. You do a lot of claiming and literally no sourcing. Try again, this time with data.

[scythe]

It doesn't exactly help that tall office buildings are not allowed in DC. It's hard to have a "hub" when it's illegal to build a hub.

>You want to know what the future of America looks like? Go to the Dallas suburbs.

Can I point out the irony that you're posting this in a thread about a natural disaster exacerbated by suburban development patterns, and your example of Dallas suffered a similar disaster less than a year ago, made worse by the thermal inefficiency of the same development patterns? Is that the future we should want?

[worstestes]

Also, Dallas is the anti-thesis of good urban design. The I-35 corridor in the area and the surrounding metroplex is a damn nightmare, and only getting worse.

[baq]

If you design your space for cars as the mode of getting to places, you get exactly that… but it really doesn’t have to be like this. It is possible to plan cities in a way that public transit works. Obviously it won’t if you need to jump into a car to buy bread for breakfast, because otherwise you won’t be back for dinner.

I say this as a member of a two car family who routinely ferries children to places and hates every minute of it that could be spent paying attention to something other than the road.

[vjust]

Right on.

I lived literally next to Dulles International Airport - ~8 miles. Yet, to get to Dulles (or Reston/Herndon) by Public transit, would've taken me 2 hours perhaps, or more.

[alistairSH]

Ha! I live in Reston and mapped out some options on Goole Maps...

Home to IAD by car: 5 miles, 9 minutes

Home to IAD by transit: 40+ minutes across 2 bus lines

Home to IAD by foot: 10.9 miles, 3+ hours

Home to WAS by car: 24 miles, 29 minutes

Home to WAS by transit: 90+ minutes across 1 bus line, 2 Metro lines, and a few walking segments to link them.

It's sad that walking to the airport is twice as far than driving. It's also sad that I can drive to a airport further away than I can access my closest airport by transit.

[stransky]

You forgot to include time to park.

[alistairSH]

Fair enough, I always take a cab/Uber to IAD, as that cost is far less than the price of parking. And living so close to IAD, I try to fly out of it whenever possible (all work travel, 80% of pleasure travel).

[rayiner]

Parking at IAD is a cinch.

[0_____0]

8 miles in 2 hours? That's a brisk walk!

[aidenn0]

Except (unless they've built new paths since I last checked) you can't realistically walk to the airport either. The only non-limited-access highway entrance is on the north side of the airport, so unless GP lives in Ashburn, you'll have to walk around the airport first (and if you're east, that means finding a decent crossing for Route 28...). Then you have such pedestrian friendly places as this[1].

1: https://www.google.com/maps/@38.9768706,-77.4451826,3a,75y,2...

[0_____0]

My reply was a comment on the average rate of travel, not a suggestion to walk to the airport.

I have considered cycling to the airport in my area before, and basically run into the same issue you raise.

[worstestes]

The future is Dallas suburbs? Let’s just call a quits now and save America the trouble

[NikolaeVarius]

Seriously, suburbia is hell

[dionidium]

This arrangement is the result of one of the biggest social engineering projects in human history. In order to make this happen the federal government had to massively subsidize loans for single-family homes, build enormous interstate highways (that always seem to be adding a lane), and make alternative living arrangements illegal via zoning.

I read your comments downthread, which I think are pretty insightful; it may be the case that the ship has sailed and we're not going back (and it may even be the case that there's something in our national DNA that prevents us from competently building and operating transit). But it should at least be acknowledged that the status quo isn't the result of personal choice or revealed preference; it was quite literally a big-government social engineering project.

[polygotdomain]

I just want to say that the comments about public transport in DC are spot on. It's incredibly hard to design a system that can actually get people where they need to be because A) people are so spread out, B) everyone is going to different places, C) there is minimal incentive to make public transit better because costs completely outweigh potential ridership.

It's sad, but without a car in the DC area, your options are very minimal and you pretty much have to live in the city.

I lived in the DC area for nearly 30 years and moved out right as Covid hit, and have tried to use public transit at various points in my adult life. Unless you live super close to a metro stop and/or need to go to a metro stop the system will barely work for you, and even then you'll be hamstrung with where you can go and how long it will take you to get there.

[R0b0t1]

Use public transit to incentivize development.

[selimthegrim]

>You want to know what the future of America looks like? Go to the Dallas suburbs. That’s where all the immigrants with kids are, and where the next generation of Americans are being raised. It’s a glorious place. And it doesn’t involve public transit.

Dallas should probably get some better research universities if this is going to be a thing.

[animal_spirits]

Correct, The Downs-Thomson paradox [1] is a known issue in urban planning stating basically unless you improve public transportation car congestion will continue to get worse.

> the equilibrium speed of car traffic on a road network is determined by the average door-to-door speed of equivalent journeys taken by public transport.

NotJustBikes has a good introduction to it [2]

[1] https://en.wikipedia.org/wiki/Downs%E2%80%93Thomson_paradox

[2] https://youtu.be/RQY6WGOoYis

[wyager]

There is no economical way for public transportation to cover the kind of transit patterns serviced by highways. If I had to take buses from Bozeman, MT to Boise, ID, any plausible bus network would take 5x as long to get me from A to B.

Making everyone ride busses and bicycles in a country with the geography of America is a fantasy, even if you buy the premise that this is otherwise desirable.

I don't even buy the premise, because things that are valuable to me include:

1. Expediency

2. Comfort

3. Not being subject to timetables decided by other people

4. Not having to deal with homeless or crazy people while transiting

5. Sanitation. Public transit and pandemic mitigation measures are mutually incompatible

While driving, I only have to deal with one network topology (the road system) instead of two (the bus network on top of the road network), leading to vastly shorter travel times in practice. My vehicles are customized to my comfort. I don't have to get permission or wait on someone else to use them. I don't have to share them with anyone. I can keep them as clean as I please.

[andrewflnr]

I don't understand why public transit doesn't have exactly the same induced demand problem as highways. If there's enough people to fill up new highways, they'll also fill up the public transit... Unless the plan is to make public transit miserable enough that only outside with no better options will use it, in which case it seems like it's all going according to plan already.

[asoneth]

Increasing public transit capacity does induce demand. In areas with excellent public transit people choose to live further away from work, take more discretionary trips by transit, etc. (That's one reason I would be wary of making transit free as some politicians have proposed.)

One reason many people are more concerned about inducing driving demand is that private vehicle travel generally emits more carbon, uses more valuable land (e.g. parking, highways), and results in more fatalities per person per mile than comparable forms of transportation.

Another problem with inducing driving demand is the degree to which those costs are subsidized by taxpayers (roads, highways), other shoppers (required/subsidized parking), or left as externalities (carbon, noise). Tolls, gas taxes, per-mile fees, and parking fees would have to be quite a bit higher in most places to cover those costs.

[azylman]

The way that public transit scales to meet higher demand is different than roads. Whereas roads require more lanes, public transit such as trains can scale by either adding more train cars to existing trains or adding more frequent service. More frequent service, in addition to improving throughput, also helps everyone else using the system by making it more convenient. And, if it "induces" people to move from roads to trains, that also reduces congestion on the roads. So induced demand for rail lines is a good thing.

If induced demand is high enough even that, too, may not be enough - but then building a new rail line is at least no harder than adding a new highway lane (in most cases), and can support substantially more throughput with equal or lower travel times.

[njarboe]

Before COVID, BART in the Bay Area was completely full during peak hours. You had to wait for multiple trains to finally pack into the car. That, or take the train the opposite direction for a few stops from downtown and then get back on in the other direction. They are starting to remove more and more seats to pack in more people, but eventually if use keeps increasing you will have to build a new subway and who knows how much that will cost or how long it will take. It is probably not really possible right now. See the failure of California's bullet train.

[azylman]

Yup, this is a big reason why I said "in most cases" and not "in all cases". When your trains have to go underground and underwater and your highways go over roads and over bridges, that dramatically changes the numbers. Of course, none of those are a requirement of rail systems - just how the BART is built. There are plenty of trains that go over roads (e.g. the L in Chicago) or over bridges over water.

By the way, even BART could increase throughput today without adding more lines. Not all trains are 10-car trains, because they don't have enough cars in the fleet. Adding more cars to their trains is a significantly cheaper prospect than adding a new lane to the Bay Bridge (which was also basically fully maxed out on throughput during peak traffic times, pre-COVID). And BART carries substantially more people across the Bay than the Bay Bridge does.

So, certainly the BART needs more capacity, both now and in the future - but so do the highways.

[dekhn]

Bay Bridge 260K ppl/day + San Mateo Bridge 93K ppl/day is within spitting distance of BART (411K ppl). If there was another whole bridge across the bay (well, maybe two or three) it would alleviate the Bay Bridge and the traffic around it.

[azylman]

Building an entirely new bridge isn't going to be cheaper than adding more cars to BART. Even assuming it was (which it wasn't), it's not going to help as much as you think it is. Not sure if you've ever commuted on the San Mateo bridge, but it's basically fully backed up from the exits onto 101, because 101 is also grid-locked. So in addition to building an entirely new bridge (which, again, more expensive than adding more cars to BART), you also need to add more lanes to 101.

[asdff]

Increasing service is very difficult to do. For example, before the pandemic I would take the red line in LA which would be packed to the brim by the time it rolled into downtown LA, not enough room to even turn around while standing. During my commuting I would do a lot of reading about transit and about the redline in particular.

To increase the capacity of the red line would take a lot of work that would not be cheap. For instance, the length of the trains could be increased, but to do that you have to construct new stations, since the train is already the length of the entire platform, at least the ones used for rush hour. LA has actually lengthened platforms that are on the surface before to accomodate longer light rail trains, but underground this is so much more difficult.

You could lower headways from the 10 minutes they are currently at, but this becomes a physics problem fast. One issue is a lack of turnback stations at the ends of the line so the train has to come to a stop then 'reverse' at the end. Another issue is a subway with a train works like a pneumatic tube, there is a volume of air moving that needs sufficient ventilation, which is why you see these big ventilation grates on sidewalks where subways run below, and to run more frequent trains would require significant upgrades to the ventilation systems along the entire line.

[azylman]

That may be the case for LA, I'm not familiar enough with their situation to speak to it, but it isn't the case generally. There are lots of rail lines in the US and globally that have not come anywhere close to maxing track capacity. One such example is BART in SF, which could just add more cars to existing trains and see 60% increase in capacity [1]. The tracks and stations support trains up to 10 cars long, but very few are actually that long enough because they don't have enough cars in the fleet.

[1] https://www.bart.gov/about/projects/cars/faq

[mrsuprawsm]

This is a case of under-investment and poor design. The London Underground, for example, the oldest underground railway in the world, manages 2-3 minute headways (29 trains per hour) on many central lines, both sub-surface and deep level.

Of course, you need to invest in the infrastructure to make it work, but it's very possible.

A quick Google suggests that in Tokyo they even hit 50 trains per hour, so one every 1m20s, which is insanely impressive.

[andrewflnr]

I don't buy the lower travel time thing, not unless your trains or whatever are running every five minutes. In practice public transit has always at least doubled my travel time. Waiting at stops (a) introduces substantial latency that (b) is unpredictable, forcing me to pad my travel times further. I mainly use it to avoid parking at the destination.

Mostly DC metro rail and a bit of LA buses, FWIW.

[azylman]

DC and LA are both infamous for having bad public transit systems, so don't base all your decisions on your experience there. Within the USA, Chicago is really good - taking the L is way faster than cars because you get to skip road traffic and the trains come very frequently. I've heard mixed things about NYC (some very positive, some very negative, likely depending on where you're traveling from/to), but have no experience there myself. Outside of the USA, there are lots of countries with fantastic train systems (e.g. Hong Kong) that are way better than driving.

[asoneth]

Besides NYC that's been my experience as well -- US cities are designed for driving as the primary transportation method. Even mass transit in the US is often pitched as something to make life easier for drivers by lowering traffic.

Lots of places talk about the importance of walkability and mass transit but if you actually look at most transportation budgets the vast majority goes to automobile infrastructure. Even what passes for "pedestrian infrastructure" in many places is there for the benefit of drivers[1]. I mean, it makes sense because everyone in the US drives everywhere, but it's a chicken-and-egg problem.

[1] https://www.strongtowns.org/journal/2021/1/29/pedestrian-inf...

[tshaddox]

I think that technically the same problem exists with public transit. It's just that the constant factor people-moving density difference of multiple orders of magnitude gives you a lot of headroom.

Of course, there are also other potential advantages of public transit unrelated to induced demand, like pollution, safety, cost, impact on the design of living spaces, etc.

[meheleventyone]

Improving public transport absolutely does induce demand and that’s part of the point of making it better. In particular because it’s much more space efficient it also reduces congestion as people switch to it. Same thing with improving cycling facilities.

It’s just inducing demand on an already overused system like private cars doesn’t fix the system being overused unless you can get beyond the desired capacity.

[njarboe]

Most people prefer individual transport systems for many good reasons. "Induced demand" is just more people using new roads because they get to do what they need/want to do. If we build enough roads (maybe using tunnels underground, a la The Boring Company) for everyone to go where they want, when they want, with up to 40 tons of cargo with them, there won't be any traffic congestion. This happened when the interstates were first built in the US and we could have that again if we decided to build thousands of miles of new tunnels. That would be a true national infrastructure project that would make everyone's lives much better. Sitting in traffic is a scourge on humanity. These tunnels could also have buses and groups of buses (trains?) in them for people who would rather travel with strangers, following a schedule set by someone else, and not carrying many objects with them. Could constructing this system also be called large-scale investment in public transportation then we could get everyone on board? Win-win solutions in society are still possible I hope.

[bluGill]

individual transport vs shared is a matter of compromise. Human drivers only go fast (when there is no congestion the autobahn with no speed limit doesn't in practice move any faster than US freeways for the majority of users of each). Trains today have the ability to go faster than human drivers. Trains carry far more people than cars. Thus replacing most trips with train trips would be faster and cheaper for most people.

Note that I said most trips there. If you don't have a system useful enough that most people use it most of the time then people still need cars to get around and that changes the calculation. it can be very hard to get there.

[AnthonyMouse]

> Additional highways are at-best a stop-gap for day-to-day traffic, never a solution, due to induced demand

This continues to be wrong every time someone brings it up.

If you have insufficient road capacity, you have congestion, and congestion suppresses demand. If you increase capacity, some of the congestion goes away, and then some of the demand comes back.

What this looks like is that you currently have enough cars to require three lanes but have two lanes, so you build a third lane. The reduction in congestion causes you to have enough cars to require four lanes, leading to the fool's conclusion that adding enough lanes is impossible. But that's not it. It's that you needed four from the beginning to handle the amount of traffic that occurs there in the absence of congestion, but you only had three, or two.

Sometimes building a four (or five or six) lane highway isn't the best solution. Sometimes it's better to build more housing near the jobs so people have shorter commutes, or build mass transit etc.

Sometimes you just need a wider road. Pretending that's never the case is preposterous. If that was true then why do we keep multi-lane highways open instead of closing all but one of the lanes? Wouldn't that improve traffic, under this theory?

[azylman]

> Sometimes you just need a wider road. Pretending that's never the case is preposterous. If that was true then why do we keep multi-lane highways open instead of closing all but one of the lanes? Wouldn't that improve traffic, under this theory?

You're setting up this strawman where the argument is "improve roads" vs. "do nothing". That's obviously not the case. The argument is "improve roads" vs. "improve public transit". Demonstrably, improving roads is worse than improving public transit. You refer to this as a "fool's conclusion" yet this has been a well-known fact in the field for almost a century. The wikipedia article I linked has some good information on this if you'd like to learn more.

[AnthonyMouse]

> Your setting up this strawman where the argument is "improve roads" vs. "do nothing".

Your claim is this:

> Additional highways are at-best a stop-gap for day-to-day traffic, never a solution, due to induced demand

That claim is false and is not a straw man because you actually claim it.

Improving mass transit might work as an alternate solution, sometimes, in specific contexts.

That doesn't prove that adding more lanes wouldn't also work, and it's also not universally true.

A large fraction of the traffic on I-95 is trucks. How many semi truck drivers and their loads can you fit on a public bus?

Many highways are congested at a specific choke point. You could make a completely free thousand mile an hour bullet train to transport people from one side of the choke point to the other and solve nothing because people would get to the other side without a car and be unable to get the last ten miles to their destination. But once you get past the choke point, the traffic diverges in every direction and there is no longer enough density to justify a mass transit route.

Sometimes you just need a wider road.

[azylman]

Maybe try quoting the entirety of what I said?

> Additional highways are at-best a stop-gap for day-to-day traffic, never a solution, due to induced demand [1]. You really need large-scale investments in public transportation for this.

Clearly "improve roads" vs. "improve public transit"...

> How many semi truck drivers and their loads can you fit on a public bus?

You're again arguing against something no one ever said. No one suggested that we should just remove all semi-trucks and replace them with buses. Again, we're discussing where to allocate incremental improvements to existing systems. No one is suggesting doing nothing or, worse, shutting down existing systems.

Using your specific example of semi-trucks, moving more traffic (such as daily commute) to rail lines or buses can actually help semi-trucks as well, by freeing up road capacity for things that actually need it. And additionally, freight trains already make up a fairly large percentage of our freight network (~30%) so rail is actually a great alternative to semi-trucks in many cases.

[AnthonyMouse]

> Clearly "improve roads" vs. "improve public transit"...

You: Cars are never a solution because they can't go faster than 15 MPH. You really need horses for this.

Me: Cars can go faster than 15 MPH in many cases. Horses can't be used to transport industrial boilers and such.

You: Clearly you missed the part about the horses.

> No one suggested that we should just remove all semi-trucks and replace them with buses.

You have a two lane road that needs to be a four lane road to handle the amount of traffic it would have without congestion.

If more than half of the traffic that would occur without congestion is trucks, you physically cannot relieve the congestion with mass transit, because relieving the congestion would require removing more than 100% of the non-truck traffic.

> Moving more traffic to rail lines or buses can actually help semi-trucks as well, by freeing up road capacity for things that actually need it.

This the other stupidity with induced demand. It's not induced, it's suppressed by congestion, which means that any alternative means of relieving the congestion will also restore the demand.

Suppose you actually built mass transit and removed the equivalent of one lane worth of traffic from the road. Now you still need to add the other lane because the reduction in traffic congestion restored demand for the road and offset what was removed by the improved mass transit.

[asoneth]

Just to be clear, the "induced demand" that concerns me is not the latent demand of a few deferred trips being taken in the days/weeks/months/year after the road is widened, it's the long-term generated demand of people choosing to move further into the suburbs because they can commute more miles in the same number of minutes. The cumulative result is that property values on the periphery of the commuting zone increase and within a decade or so the highway traffic exceeds the optimal capacity again.

Some regions have concluded that adding a lane per decade is sustainable and already have highways more than a dozen lanes wide. I'm curious to see where the upper bound is.

(Personally I think dynamic pricing to maintain optimal highway capacity is a more sustainable approach.)

[AnthonyMouse]

> Just to be clear, the "induced demand" that concerns me is not the latent demand of a few deferred trips being taken in the days/weeks/months/year after the road is widened, it's the long-term generated demand of people choosing to move further into the suburbs because they can commute more miles in the same number of minutes. The cumulative result is that property values on the periphery of the commuting zone increase and within a decade or so the highway traffic exceeds the optimal capacity again.

Property values increasing there actually offsets the problem by making it less desirable to live there.

The real trouble is that people build more houses there. But the reason people build more houses there, and suffer a 30 minute commute (which more congestion might have turned into a 60 minute commute), is that they can't afford to live in the place with a 15 minute commute. Typically because zoning prohibits building more housing there.

Now let's see what our choices are here.

We can do nothing at all. Well, now people are screwed. They still need somewhere to live, the place that now has a 60 minute commute is the only place housing can be built, so the housing still gets built there, but now the commute is longer. That's just horrible and helps no one.

Second, we could widen the road and that's it. The new housing still gets built in the suburbs but at least now people waste less time in their cars.

Third, we could loosen the zoning so higher density housing can be built closer to the city, but not widen the road. This is pretty good, because now the people who live in the new housing get the 15 minute commute. But the people who already live in the suburbs are still stuck with the 60 minute commute.

Fourth, we could loosen the zoning and widen the road. Then new housing gets built in the city instead of the suburbs, because people prefer a 15 minute commute to a 30 minute commute, but the people who already live in the suburbs still get a 30 minute commute instead of a 60 minute commute because of the wider road. And it stays that way because the new housing is getting built in the city instead of the suburbs. This is pretty obviously the one that we want.

[asoneth]

> but the people who already live in the suburbs still get a 30 minute commute instead of a 60 minute commute because of the wider road

That is true for several years after the highway widening. Which is good for politicians who operate one election cycle at a time.

But the population doesn't just sit back and enjoy shorter commutes after a highway widening project. The towns that used to be two hours outside the city are now only an hour drive away and commuters looking for a deal start to move there. The towns that used to be an hour away are now only a half-hour drive to the city and are now hotter as well. Some of that is due to a game of musical chairs in which people expand out of the city to the suburbs, some of that is new residents choosing to live further out than they would have if they arrived before the highway widening. All of this increases the number of vehicle miles traveled. Eventually (over the span of decades) this results in a new equilibrium in which the highway is nearly as congested as it was before the widening and everyone is once again living at about the time-limit of how far they are willing to commute.

It's not all bad of course because the new highway helps grow the metro area and it increases property values, especially in the suburbs that were on the periphery of the commuting zones. But to permanently eliminate congestion you'd either have to keep widening the road every decade or two to handle the growth (Houston, Dallas), allow the congestion itself to act as a natural limit (NJ), or institute tolls/congestion pricing (Singapore, London).

[AnthonyMouse]

> But the population doesn't just sit back and enjoy shorter commutes after a highway widening project.

Notice that this is true of anything that relieves the highway congestion in any way whatsoever. As soon as the road is clear, no matter why, the commute is shorter and it becomes more attractive to live further away in distance.

> Eventually (over the span of decades) this results in a new equilibrium in which the highway is nearly as congested as it was before the widening and everyone is once again living at about the time-limit of how far they are willing to commute.

The way out of this is to make some alternative to increasing sprawl more attractive than increasing sprawl. Relaxing zoning rules to allow higher density is an obvious one, because people would rather have a 15 minute commute than a 30 minute commute, so they'll prefer to build housing where it's a 15 minute commute unless that's prohibited by law. When it is, they have to build further away and you get more sprawl.

But also notice that you're assuming population growth.

If the population was stable, and you built a road which is sufficient now, it'll probably stay sufficient as long as the population remains stable, because who is building enough new housing to move the needle on traffic in a city that isn't growing?

If the city's population is growing, continued population growth will require you to expand highways and such over time in proportion to the population. What else would you expect? The only alternative is intentional scarcity.

[asoneth]

> Notice that this is true of anything that relieves the highway congestion in any way whatsoever.

Is that true if we charge an appropriate price for road use? Isn't that what we do to manage availability of every other scarce resource to ensure it is being used optimally?

If you increase the price of using the road at the busiest times then eventually you will arrive at a price that maintains the optimum flow rate. You may need to adjust the price occasionally to track shifts in inflation and population, it has equity issues, and (like most sustainable solutions) it is politically difficult. But I don't understand what would cause it to stop working. In the places it has been implemented (e.g. Singapore, London, Stockholm) it is generally unpopular at first and then extremely popular after a year or so. And administering it should become cheaper as technology improves which may make it feasible for smaller cities as well.

> If the population was stable, and you built a road which is sufficient now, it'll probably stay sufficient as long as the population remains stable, because who is building enough new housing to move the needle on traffic in a city that isn't growing?

Even in metro areas that have stable populations, heavily subsidizing transportation infrastructure (whether transit or highways) between the city and the suburbs often has the effect of slowly shifting the current metro population outward to those suburbs. By subsidizing suburban commuters you are making living in the suburbs more attractive than it would be otherwise. As you make it more attractive, more people who currently live in the city will rationally choose to move to the suburbs.

I'm not saying it's a bad idea to build more lanes, just that on it's own it is not a sustainable approach. As long as rent/land prices are largely set by the market and roadways are free or heavily subsidized then it's not surprising that people take advantage of that and you end up with a shortage of road space.

(I agree with your comments on zoning.)

[_dain_]

You're missing half the story; "demand" only makes sense with reference to a price. At the moment, that price is zero, but it needn't be. As we all know, market prices are an efficient mechanism to allocate scarce resources. People have a curious blindspot about this when it comes to roads.

[AnthonyMouse]

> As we all know, market prices are an efficient mechanism to allocate scarce resources. People have a curious blindspot about this when it comes to roads.

It's not a blind spot. It's a characteristic of services with a high fixed cost and trivial variable cost.

To ask if we should price roads is to ask if the price needed to deter usage enough to relieve congestion without expanding the road would generate less revenue than it would take to expand the road. But this is basically never the case because most of the expansion cost is one-time (e.g. buying the land) whereas the congestion charge would have to be collected forever to continue deterring usage.

The strongest case for not expanding the road is if there is a more efficient way to relieve congestion, e.g. by relaxing zoning restrictions to allow higher density housing and reduce travel distances.

But if people value using the road at more than the cost of expanding it, and there are no higher efficiency alternatives, that implies the road should be expanded. And once it has been and there is no congestion even at zero unit price, there is no benefit in charging a unit price to deter congestion that isn't there anyway, and a detriment in deterring use of a public resource for which the same fixed cost has to be paid whether you use it or not.

Charging road tolls is also especially inefficient because the collections process has a high administrative overhead and a high privacy cost. Every dollar spent collecting tolls -- toll tags, gantries, billing, maintenance, customer service -- is a deadweight economic loss not incurred by any alternative that doesn't require them. The privacy cost is the same.

[_dain_]

>To ask if we should price roads is to ask if the price needed to deter usage enough to relieve congestion without expanding the road would generate less revenue than it would take to expand the road. But this is basically never the case because most of the expansion cost is one-time (e.g. buying the land) whereas the congestion charge would have to be collected forever to continue deterring usage.

First of all, that just doesn't follow. You can take out a loan to pay for the up-front cost and pay it back using the revenue you collect from tolls. Second, roads cost a lot of money to maintain. There are the usual ongoing costs to fix potholes and so on, and then they have to be totally replaced after 25-30 years. This is far more than what local taxation can bear in many cases. Replacement costs are chronically underestimated.

(e.g. Winnipeg would have to raise taxes 95% to properly fund their existing road liabilities: https://www.strongtowns.org/journal/2021/1/3/death-of-a-car-... )

>But if people value using the road at more than the cost of expanding it, and there are no higher efficiency alternatives, that implies the road should be expanded.

This is wrong, they are not valuing it properly because it is paid for by taxation and debt. A motorist pays exactly the same amount directly as a non-motorist: zero. The true costs are diffuse, invisible, and incomplete.

>And once it has been and there is no congestion even at zero unit price, there is no benefit in charging a unit price to deter congestion that isn't there anyway, and a detriment in deterring use of a public resource for which the same fixed cost has to be paid whether you use it or not.

This situation hardly ever happens. There is almost always more congestion after expansions than predicted by planners. If you wanted to overpower induced demand and get rid of all congestion the roads would have to be utterly gargantuan.

>Charging road tolls is also especially inefficient because the collections process has a high administrative overhead and a high privacy cost. Every dollar spent collecting tolls -- toll tags, gantries, billing, maintenance, customer service -- is a deadweight economic loss not incurred by any alternative that doesn't require them. The privacy cost is the same.

Time spent stuck in traffic is also deadweight loss, and it creates pollution.

[AnthonyMouse]

> You can take out a loan to pay for the up-front cost and pay it back using the revenue you collect from tolls.

The fact that you can do this is the point. It means the value of expanding the road is more than the cost of expanding the road, which implies it should be done absent some better non-toll alternative like increasing housing density.

But once you have enough capacity that there is no congestion without congestion charges, it's inefficient to deter use of the sunk cost road.

> There are the usual ongoing costs to fix potholes and so on, and then they have to be totally replaced after 25-30 years.

These costs aren't linear in the number of lanes. Resurfacing a four lane highway doesn't cost four times more than resurfacing a one lane highway (or your contractors are ripping you off).

Moreover, the initial cost is typically the highest, because you have to acquire land and possibly rebuild bridges and overpasses the first time.

> This is far more than what local taxation can bear in many cases. Replacement costs are chronically underestimated.

This applies to roads to nowhere that are under-utilized but still have to be maintained. Anything with traffic congestion is seeing more use than its cost.

You also have problems with corruption in government contracting inflating the cost of everything, but that's a separate problem and applies equally to mass transit etc.

> This is wrong, they are not valuing it properly because it is paid for by taxation and debt. A motorist pays exactly the same amount directly as a non-motorist: zero.

It's not a question of what they're actually paying, it's a question of what they would be willing to pay, i.e. the value they assign to the road. If you put a toll somewhere there is congestion, would the toll pay enough to expand the road? The answer is almost always yes, which implies that that the road should be expanded when congestion exists, unless there is some more efficient alternative to relieve the congestion.

It shows that expanding the road is more valuable than deterring usage with tolls. The possibility remains that some non-toll method of relieving congestion is still better than expanding the road, but it shows that expanding the road is better than deterring usage with tolls.

And whether to expand the road is a separate question from whether to actually fund the expansion from the tolls, because toll collection is inefficient and privacy invasive the deterrence function is undesired when the congestion can be relieved without it. The toll being able to fund the road proves that people value the road at more than its cost, but it's not the most efficient way to fund it.

> If you wanted to overpower induced demand and get rid of all congestion the roads would have to be utterly gargantuan.

This is only the case if you for some reason insist on using road expansion as the only solution to relieve congestion.

Mass transit can relieve congestion in higher density areas. Zoning that allows higher density housing to be built near jobs relieves congestion by both reducing the distances people have to travel and making mass transit more efficient.

Expanding roads works where those don't, or in combination with them. For example, if you have a growing city with restrictive zoning and a congested road between a large suburb and the city center, what you want to do is cause new housing to be built closer to the city instead of further expanding the suburbs, but the road to the suburbs still needs to be expanded because it is already too small for the existing traffic from housing which is already there and is not about to be removed.

This is politics. The most effective solution involves allowing higher density housing near urban areas, but this is not the solution desired by existing land owners, so they push inefficient alternatives like tolls. Because that increases rather than decreases property values closer to the city center by making it more expensive to live further away without increasing the supply of housing that isn't further away, so existing land owners collect higher rents to the detriment of residents.

> Time spent stuck in traffic is also deadweight loss, and it creates pollution.

Which is why we should relieve congestion by using the alternatives with fewer deadweight losses, like building higher density housing where that works and expanding roads where that works.

[tshaddox]

But there is some limit to the number of lanes you can add, even theoretically from a topological perspective, but more imminently from a practical standpoint of limited budgets and ability to tear down existing non-road infrastructure.

[AnthonyMouse]

The theoretical limit is irrelevant. It's like saying you can't always improve emergency response time because of the speed of light. Nobody is really up against the theoretical limit.

The practical limits are all trade offs. How much does it cost to add two lanes? How much does it cost to maintain low ridership bus service to low density suburbs? There are circumstances in which adding more lanes is the best available alternative.

[erik_seaberg]

“People drive more instead of giving up and staying home” is latent demand being met. “People drive more because building the highways made everything farther apart” is induced demand being created.

[mrfusion]

I love how people think induced demand is an iron clad argument against any road building.

What about the induced demand of going from 0 lanes to 1 lane?

[yifanl]

Depends on where that 0 lanes is initially I guess. You can bulldoze a housing block to add a new lane, that's not necessarily an economic success.

[asdff]

It is if destroying those ten houses relieved a trucking bottleneck at the train yard.

[yuliyp]

Is there really that much induced demand in rural interstate highways? They're congested rarely enough and still almost everywhere the standard 4 lane interstate can handle things without seeing demand fill the available capacity. Certain corridors see increased demand at times but that's because of the surrounding communities happening to grow (and thus need more goods delivered / ability to ship goods) more than the highways necessarily inducing that growth.

I understand that induced demand is a thing in sprawling metropolis where transport is the bottleneck preventing growth in certain areas, but this feels like a different situation.

[dave_aiello]

HOV lanes, special toll lanes, driverless vehicles, new alternative means of transportation that never quite materialize, etc., don’t cut it and never did.

[massysett]

The idea that highways are “never” a solution due to induced demand is an utter falsehood. It may well be that the expense of sufficient highway capacity is, in some cases, more than society is willing to bear. But that does not mean that highway construction is “never” a solution.

[adventured]

> never a solution, due to induced demand

That's false. The mistake universally made by people repeating that claim is a failure to account for the fact that vehicles and population are finite. In the US there isn't much population growth, except for in a select few urban areas. It's baffling that it gets repeated so often as though it's always true, when it's not. You can swamp the amount of induced demand with additional roads, it all depends on the number of vehicles you're dealing with. Which is to say, it depends on context and it's incorrect to suggest matter-of-fact that induced demand defeats additional roads.

You'd need to run a study on the traffic potential and local + regional population growth to know one way or another what additional roads might do as it pertains to inducing demand over time and whether you can overcome the expected increased demand. The demand doesn't just keep rising forever as you build more roads.

[_dain_]

>You can swamp the amount of induced demand with additional roads, it all depends on the number of vehicles you're dealing with

Do you realize just how extravagantly expensive that would be?

[trhway]

public transportation doesn't work for people with pets, in many situations for people with children, people with various health issues.

[acdha]

> public transportation doesn't work for people with pets, in many situations for people with children

Do you mean the millions of people who do this every day don't exist? You might personally prefer that and it's certainly an opinion which has been lavishly subsidized in the U.S. but this is a lifestyle choice, not a truth.

> people with various health issues.

How many of the people who cannot take transit are capable of safely driving cars? Public transportation — whether bus/rail mass transit or on-demand access services — is key for a large number of people who cannot drive themselves and a large number of people who could but are not affluent enough to afford the $10K/year or more that personal car ownership (considerably more if you need a vehicle customized with assistive technologies).

Again, you obviously have an opinion on this issue but that doesn't make such blanket statements less incorrect.

[trhway]

It isn't a preference nor choice. It is direct experience. More than half of my life i was using public transportation in USSR/Russia, no issues, we'd take our cats/dogs when needed. Not the case in US.

>How many of the people who cannot take transit are capable of safely driving cars?

It doesn't matter how many (though a lot of people for example develop back issues by mid age and beyond so prolonged walking/standing is much harder than sitting in the car especially after a workday). The point is you just dismiss them. And this is why those tone-deaf public transportation proponents like you aren't going anywhere - you dismiss all those supposedly small groups and thus as a result left with pretty much no support.

And just a bit of meta to illustrate the point - notice that i'm telling you about the issues with your approach and instead of addressing them, you're dismissing them outright as supposedly just "my preferences".

[acdha]

> The point is you just dismiss them

This is pure projection: I was pointing out that millions of people's daily life contradicted the absolute statement you made. If you'd said “doesn't work for many people” I would have agreed: it's no secret that the U.S. has heavily subsidized car-centric design for the last century and there are many people living in neighborhoods which don't even have sidewalks, much less transit or bike paths.

This has also encouraged many people to think that they must drive even if it's not a great choice: in the city I live in, it's not uncommon for people to cling to the habits they acquired growing up and trying to drive everywhere even though it means they're paying considerably more to sit in traffic while their friends who biked or took the train wonder why they're late.

There isn't a single answer here but the important thing is remembering that these are choices. Giving private car owners exclusive use of public land might be a popular choice but it's not a law of nature, and when it doesn't work well it's reasonable to question whether it's the right design for the context. There's no reason to think that the same answers will be true in rural areas, suburbs, and dense urban cores.

[enragedcacti]

they can still drive?