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Roads aren't a great comparison because there is legitimate induced demand for roads - if you build more roads, and the roads are not at capacity, those around
by zanny 7y ago
Roads aren't a great comparison because there is legitimate induced demand for roads - if you build more roads, and the roads are not at capacity, those around the roads will trend towards more car ownership, more frequent usage of the roads, the range of commute using said roads will grow larger and larger, and people will immigrate and build up sprawl to fill those roads.
This keeps happening for any practical width of road, because in practice you can't really have a 30 lane wide highway. Automotive travel is inefficient enough that even at suburban density you can always congest any road network you build around it.
This does also apply to housing - even at the highest densities you can get, rivaling Hong Kong, there are too many people in the world for anyone city to ever build enough housing to legitimately run out - density itself creates economic multipliers that attract business, and if you were to have some of the highest density in America (which is largely the claim of NY) you would have effectively unlimited attractants for capital to fund immigrants to move into said city and populate it. In the scenario where you "overbuild" high density housing to the point where the next poorest local cannot afford it at its upkeep costs you would attract foreign immigration for the cheap housing with ample employment opportunity.
Note that that last scenario assumes all other variables are held constant - desirability, transit supply per-person, availability of public services like fire and police, etc. Missing other variables can make high density areas undesirable for capital and thus prevent the chain reaction.
- bluGill 7y agoMost people have ideal commute distances of about 30 minutes: Note clearly that my distance unit is time. Anything within 30 minutes, regardless of transport modes, is close, anything more is far. Eventually the time to get to the inner lanes is longer than 30 minutes and you cannot go wider. Of course this is reduction to absurd. Roads can go up (or down) quite a bit though. It is expensive (much more expensive than adding more lanes) which is why we rarely do it. Even when/where we have, we would have to go more than we have to get ahead. My point is you can get ahead of induced demand. I know a farmer who planted right across a public road - technically illegal, but the neighbors didn't use that road anyway. When you get in a city is is harder - by enough that it isn't worth it - but you can. (Cities should of course have more public transit which gets ahead much quicker). You are correct that cities building - at affordable rates - do attract people. However if the city allows building over the long term we know from existing examples it gets out of it. Chicago and Huston don't have housing price problems because you can build there. Now we do need to be clear: it costs money to build. New houses are always higher end. How high depends, if only a few houses can be built, they will be mansions. Once demand for mansions is filled builders move down market to lower profit houses until it is no longer feasible to build anything (humans don't fit in a doll house). The paper is no only slightly better supported by data than my arguments above and really isn't useful.