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> The problem is that cars don't scale. this isn't very useful. all modes of transportation have scaling limits where it becomes cost or space prohibitive to i

> The problem is that cars don't scale. this isn't very useful. all modes of transportation have scaling limits where it becomes cost or space prohibitive to increase capacity. interestingly, trains have many of the same issues as cars. mostly empty trains are not cost efficient, and finding space to store out-of-service rolling stock is a non-trivial problem in transit systems for dense cities. it's not obvious at first, since trains do have a huge space efficiency advantage to begin with, but subterranean space is extremely expensive when you need to build more. there is also a tradeoff between cost and space use. we don't think of space (in the basic geometric sense) as the main constraint on the capacity of the subway, because there is obviously a lot more room for tunnels into and under manhattan. it's just not economic to build them right away. but you could also build multi-level freeways and underground parking garages with vehicle elevators. it's definitely not economic to do that today, but it might be at some point in the future. a final observation and bit of a tangent: we build most transportation systems (cars, buses, trains) to have capacity that is only needed for a few hours each day, and often only in one direction. why do we not question more the basic assumption that a large fraction of an urban catchment area's population needs to commute back and forth from many distant residential areas to a single downtown core every day? I'm not just talking about WFH here. why do we not incentive more local clusters of work locations? it seems to me that a lot of the scaling problem would be solved if we worked closer to where we live.

adrianN 3y ago
Finding space to store out-of-service cars is literally turning cities into agglomerations of parking spots. I don't think trains, busses, and bicycles pose a similar level of difficulty.
xp84 3y ago
> would be solved if we worked closer to where we live. You're really not wrong, but also, it is a real heck of a problem to rein in. Allow me to digress for a moment and then I'll tie it back: I arrived at the induced demand conclusion, after thinking it was mumbo jumbo for a while, when I realized that human tolerance for misery is the constant value. Humans, in the aggregate, clearly have a tolerance for misery which exceeds that of driving for hours in L.A. traffic. Enough of them individually tolerate it in fact, to keep those traffic arteries clogged for probably up to 5 hours a day on a good day. Build a new lane or route, wait a little while, the traffic scales to keep the commute times roughly the same, because if they got any better, a couple more people would eventually decide it's worth it to go for that great career opportunity that puts them in a car 3 hours a day, or, people who were driving 3 hours a day before but found it trending to 2 would think "I could get that big new-construction house 3 towns further out and my commute would only be back to what it was before the new lanes were added. Cool!" Anyway, since the equilibrium misery level (which we can't change without mind control) isn't already enough incentive to spur them to come up with a less distant work/home separation, I'm not sure how much success any initiative to 'get people' to work closer to home would have unless it was imposed by a totalitarian state (perhaps as powerful as the Communist Party of China? Though I'm not making any specific comparisons to actual CPC actions because I don't know China well enough). People already want to, all things being equal, but they also will really want the higher-paying job -- or the many-bedroom house for their growing family -- even if it is "too far." Also, side note: suburban office buildings today are one of the most distressed real estate assets, so it seems that the idea of just providing places for work closer to suburban residential is already not finding enough buy-in from the business owners who would create these jobs.
- bluGill 3y ago
  That misery level is generally considered to be about half an hour each way. You can see this back to hunter gathers moving the camp when the herds (or ripe plants) were more than half an hour from their camp; peasant farmers keeping the village within that distance of the fields. Some people do commute much longer, but there is a clear wall around the half hour mark. The things people do when there is more opportunity are good things. That larger house is (to them) a good thing. that job was not better despite more pay because they would have to move - uprooting their family (and spouses job) to take it. This are things your city should strive to enable people to do.
bluGill 3y ago
Mostly empty trains at the peak is not efficient. However if they are 70% full at peak running them mostly empty the rest of the day is efficient enough to be worth doing (people who think they can easily get home should something happen in the middle of the day are more likely to use the train). Trains only need storage when they are out of service, or getting maintenance. The first is a bad thing to be avoided, while the second should be covered by your maintenance sheds. (You still need to store trains while doing track maintenance) Note too that trains can take the rails well outside of your city limits to be stored. You need to build that track, but you probably should anyway.

adrianN 3y ago

Finding space to store out-of-service cars is literally turning cities into agglomerations of parking spots. I don't think trains, busses, and bicycles pose a similar level of difficulty.

xp84 3y ago

> would be solved if we worked closer to where we live. You're really not wrong, but also, it is a real heck of a problem to rein in. Allow me to digress for a moment and then I'll tie it back: I arrived at the induced demand conclusion, after thinking it was mumbo jumbo for a while, when I realized that human tolerance for misery is the constant value. Humans, in the aggregate, clearly have a tolerance for misery which exceeds that of driving for hours in L.A. traffic. Enough of them individually tolerate it in fact, to keep those traffic arteries clogged for probably up to 5 hours a day on a good day. Build a new lane or route, wait a little while, the traffic scales to keep the commute times roughly the same, because if they got any better, a couple more people would eventually decide it's worth it to go for that great career opportunity that puts them in a car 3 hours a day, or, people who were driving 3 hours a day before but found it trending to 2 would think "I could get that big new-construction house 3 towns further out and my commute would only be back to what it was before the new lanes were added. Cool!" Anyway, since the equilibrium misery level (which we can't change without mind control) isn't already enough incentive to spur them to come up with a less distant work/home separation, I'm not sure how much success any initiative to 'get people' to work closer to home would have unless it was imposed by a totalitarian state (perhaps as powerful as the Communist Party of China? Though I'm not making any specific comparisons to actual CPC actions because I don't know China well enough). People already want to, all things being equal, but they also will really want the higher-paying job -- or the many-bedroom house for their growing family -- even if it is "too far." Also, side note: suburban office buildings today are one of the most distressed real estate assets, so it seems that the idea of just providing places for work closer to suburban residential is already not finding enough buy-in from the business owners who would create these jobs.

bluGill 3y ago
That misery level is generally considered to be about half an hour each way. You can see this back to hunter gathers moving the camp when the herds (or ripe plants) were more than half an hour from their camp; peasant farmers keeping the village within that distance of the fields. Some people do commute much longer, but there is a clear wall around the half hour mark. The things people do when there is more opportunity are good things. That larger house is (to them) a good thing. that job was not better despite more pay because they would have to move - uprooting their family (and spouses job) to take it. This are things your city should strive to enable people to do.

bluGill 3y ago

Mostly empty trains at the peak is not efficient. However if they are 70% full at peak running them mostly empty the rest of the day is efficient enough to be worth doing (people who think they can easily get home should something happen in the middle of the day are more likely to use the train). Trains only need storage when they are out of service, or getting maintenance. The first is a bad thing to be avoided, while the second should be covered by your maintenance sheds. (You still need to store trains while doing track maintenance) Note too that trains can take the rails well outside of your city limits to be stored. You need to build that track, but you probably should anyway.