[titzer]

> There is a 100 mile stretch of I-80...

Logistically speaking, empty places are really, really easy to build rail through. (Politically they may not be).

These rail networks already exist, but they are often not dual line, aren't engineered to support fast trains, and there aren't passenger rail options that utilize them. All of these factors are due to consistent under investment because of chick-and-egg and political problems. It's a real failure of national investment.

You can Google around but the cost per mile of new railroad track is comparable, if not a bit less, than interstate highway. And there are _tons_ of miles of interstate highways.

The US has just chosen poorly.

[ekianjo]

You can have way more passagers on a highway than on railroads though. Capacity wise cars are the better choice because its a continuous flow. Plus, they get you where you need to be, not just where the track stops.

[Johnny555]

No, you can't. A rail line can carry many more passengers/hour than cars, even self driving cars.

From https://letsgola.wordpress.com/2014/08/24/capacity-101/

A typical freeway lane today can carry around 3600 passengers per hour. Reduce the headway between cars to 1 second and put 4 passengers in every car and that goes up to 14,400 pax/hr

However, run a heavy rail line and run trains every 3 minutes, and it can carry 54,000 pax/h, or 90,300 pax/hr crush load

[ekianjo]

Even in Japan where trains are tightly operated, you don't get trains every 3 minutes (talking about long distance trains, not metros). At best one train every 15 minutes on average between peak hours and more calm periods. That divides your capacity by 5 already, so you are now at around 10 000 passengers per hour with your trains.

Add to that that freeways don't have a single lane, but usually at least 2, if not 3, according to your numbers you get 7000~10 000 passengers per hour with cars.

Now consider than most of the trains are not running full, and don't run at night at all between 10 pm and 5 am, and you can clearly see that there is an inherent advantage in terms of flows towards cars (since traffic never stops) per day. Plus you have mass transportation on freeways with buses, too.

And still the major advantage of the car is that you can stop exactly where you want to go. The train may get you from A to B, but most people want to go to C, D, E or F and not just B so trains are always a trade-off unless you have a very standard route every single time.

And I'm not even talking about cost yet. For passengers, trains are way more expensive (even in Japan, where trains are highly developed) than the same trips by car (even though the freeways are heavily taxed).

[Johnny555]

The OP was talking about max capacity not real world capacity.

Some JR lines run at 4 minute headways during peak times and subways run reliably at 2 minute headways.

No freeway today has has 4 passenger cars running at 1 second headways so you end up with a more realistic 1000 to 2000 pax per hour. Which is about the number of pax you can fit in a single train.

A 3 lane freeway takes up about the same amount of space e as 4 sets of train tracks. And the areas that have heavy congestion are also typically the areas that have little space to spare for more lanes.

The road toll from Osaka to Kyoto is $20. A local train costs about $5, a slightly faster JR train is $12. The toll from Nagoya to Fukuoka is $160 and the drive takes 9 hours. I paid about $165 for a Shinkansen bullet train that took about 3.5 hours. And the toll prices ignore the cost of the car

[wskinner]

So your point is that in ideal (not real world) conditions, trains have higher throughput. And in Japan, the cost to a consumer is higher to drive.

A) why should we care about ideal rather than real world scenarios? If the train is only 30% full on average, it doesn’t matter that if full, it would transport more pax per hour. And based on the number of cars on these highways, I don’t think the trains will be very full. If the trains are going to be empty, operating them and building the tracks is probably not cost effective.

B) Without knowing the all-in cost of the two options, comparing these prices is meaningless. It’s very likely the Japanese government sets tolls high enough to incentivize people to take trains. That doesn’t by itself mean trains are a better option... I could point to plenty of places in the USA where driving is cheaper than taking Amtrak. What does that illustrate? That American states pay for roads with taxes instead of tolls? That Amtrak is inefficient and expensive? I have no idea.

[icc97]

I think the parent's point was that you can have higher throughput on trains in both real world and ideal.

[vidarh]

To add to that:

Some London tube lines run with <100 second headway, and the highest capacity London underground trains have a capacity of nearly 1200

And my local heavy rail station regularly handles 3-4 trains to the same station in a 10 minute interval. E.g right now there are 3 trains for London Victoria scheduled to leave in a 7 minute period, and that's not peak time.

[ekianjo]

> Some JR lines run at 4 minute headways during peak times and subways run reliably at 2 minute headways.

I was talking clearly about long distance trains. Not Kyoto to Osaka distance.

[Johnny555]

JR runs long distance as well as metro trains.

[dagw]

The number of areas in the world where you have two points where it's worth running a heavy line train every 3 minutes is minuscule.

[Johnny555]

But, not coincidentally, those areas are the same areas where freeways are at capacity and would benefit from running 4 passenger self-driving cars at 1 second headways.

Self driving cars work well with railroads -- the cars can get passengers from their lower density neighborhoods to the rail stations, and rail can take the passengers to the urban centers where their jobs are. It makes little sense for a self-driving car to take a worker from his suburban home all the way to the crowded urban center where his car either needs to find someplace to park, or join thousands of other cars looking for someone else to ride until it's time to go home.

[vidarh]

That's the best part, I think, with self driving services: Coupled with other modes of transport, if we know the start and end points, we can optimize public transport accordingly, and in the meantime your car can take you to the optimal station and tell you which platform to go to and where you'll get picked up for the final leg of your journey.

You can also then optimize to drop people off at stations they might not otherwise pick if traffic makes it more sensible, or tell them to get off a station early/late and pick them up there if it helps the overall journey.

Over the long run it may even fundamentally alter construction of new lines, in that there may be more optimal location of station placements for stations e.g. feeding commuters when you have detailed data on the precise journeys.

[mercutio2]

This is the opposite of everything I’ve ever read about transportation capacity.

Trains have exceptional capacity. You can make them longer, you can increase frequency. Cars routinely max out capacity in roadways where equivalent area train systems would have vastly more capacity without breaking a sweat.

Last-mile is better for cars, though.

[mark-r]

Once you can easily hail a self-driving car at both ends of the trip, where the track stops ceases to be a problem. You can do that with cabs today, but the cost and convenience aren't where they need to be.