[zephjc]

I gotta agree with thescriptkiddie, C:S is an imperfect model of how traffic behaves.

> Self-driving cars (or just ubiquitous turn-by-turn navigation) could change this equation by intelligently routing cars around bottlenecks and avoiding the neighborhood entirely, but as long as drivers have imperfect information about traffic conditions and tend to take the shortest route to their destination, this will remain a problem.

Self-driving cars or drivers with good mapping are still limited where they can go when they have a street hierarchy to deal with, forcing all cars onto the same few arterials.

> Oftentimes, the solution to a traffic problem is simply to bulldoze a few intersections. By doing this, you give cars a buffer. It increases the median trip length but it also increases vehicle speed and road throughput by more.

This is all well and fine in a game, but increasing street speeds kills the street life (figuratively, and sometimes literally). Slower but more constant speeds are better for everyone involved. For walkers, bikers, and even drivers. Ask yourself this: would drivers flip their shit more often when going slow but steady down 15-20 mph hour streets with stop signs (or roundabouts), or when they're stuck at long traffic lights regardless of how many lanes they have?

[nostrademons]

The benefit of faster speeds isn't driver convenience, it's that you get cars off the road quicker for a given travel distance. Each city has a carrying capacity for the number of cars that may be on its roads at once, which is determined by the length of the road network and number of lanes. They also have a certain number of trips generated, which is determined by population. The number of cars on the road = trips generated * average travel time per trip. When that exceeds the carrying capacity of the city, average travel time increases, which causes a cascading effect that eventually results in gridlock.

The same effect plays out locally, on each individual stretch of road. When integral(# of incoming cars - # of outgoing cars, time) > carrying capacity of road, the road backs up, which increases the time required to traverse it, which further exacerbates the backup. This is why multi-lane arterials can reduce congestion; they can move a lot of cars off a given stretch in a short period of time, and provide a linear buffer where momentary oversupplies can collect without backing up the previous intersection.

You can also see this effect by looking at traffic maps of say, SF (grid layout) vs. Sunnyvale (arterial/collector):

https://www.google.com/maps/@37.7811106,-122.4106957,16z/dat...

https://www.google.com/maps/@37.3724565,-122.0375532,15z/dat...

Both of them have shitty traffic, but in SF the traffic spills away from Market street onto many of the side streets, such that no matter where you go it'll be gridlock. In Sunnyvale, much of the traffic is confined to major arterials like El Camino or Matilda, which are slow but still move, and side-streets that parallel them are often relatively clear.

[zephjc]

> The benefit of faster speeds isn't driver convenience, it's that you get cars off the road quicker for a given travel distance.

Yes but that isn't actually what happens because the use of a street or road isn't by one car from A to B but by the continuous use over time across a section of the street.

Say you had a single 1 mile arterial in a city, and it's the only way of getting from one half of the city to the other half. There are few points when a cars are "off" of it (except maybe late at night) - the rest of the time it is a near constant high speed flow.

You're not wrong to say that it gets any given car off the road quicker, but that is if you're focusing on the one driver's trip, as opposed to focusing on the use of and experience of being at that section of road. If it was an old town which had its main street become a high speed arterial, you now have an experience for any pedestrians who might want to use the (probably few remaining) stores along that road be not unlike walking along side a freeway - unfun and dangerous.

By focusing on any one driver's trip experience, and not the street experience, you're essentially damning the street experience for the potential sake of some extra time saved (if its across a city, perhaps on the order of 10 or so minutes).

Of course when you have nothing on the street worth being around (like most of El Camino Real), you want to get passed it ASAP. (SF problems are a whole other hairball of outside commuters plus residents who insist on using cars.)

[delinka]

Did you intend to paste the same quote twice?

[zephjc]

I did not, thank you; fixed :)