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The problem with the 'induced demand' paradigm is that it leads to cities not investing in infrastructure, and often designing the city to be hard to enter or e

by nickff 2y ago

The problem with the 'induced demand' paradigm is that it leads to cities not investing in infrastructure, and often designing the city to be hard to enter or exit, and impossible to bypass. This is one instance where there are many examples of the 'slippery slope' coming to pass. If we want people to take mass transit, we should make it better, instead of making everything else terrible.

ameliaquining 2y ago
I'm not sure I understand what you're getting at. "Induced demand" isn't a policy paradigm; it's just the observation that if you make it easier for more people to get somewhere, then more people will go there. Without congestion pricing, the only equilibrium (until you exhaust all demand, which isn't going to happen in hot metro areas) is the one where the roads are congested enough to deter the next marginal person from using them. With congestion pricing, you can choose a different equilibrium without the deadweight loss of people stuck in traffic. The question of how much to invest in infrastructure, and what kinds, can then be addressed separately in whatever way makes sense given local conditions.
- nickff 2y ago
  Everyone that I’ve ever heard mention ‘induced demand’ with respect to roads does so while advocating against the construction of additional infrastructure capacity for passenger vehicles (cars). This correlation is consistent enough that it does indicate some sort of ‘induced demand paradigm’. I agree that ‘congestion pricing’ does impact traffic, but it does so by changing the cost function, and granting the city government additional revenue from (usually poorer) people who it is not accountable to.
  - ameliaquining 2y ago
    Yes, it's definitely the case that a lot of mass transit advocates are confused about this and talk about induced demand in an unproductive way. New York City's congestion pricing scheme was approved at the state level, so it's not true that people living outside the city didn't get a say—though people from New Jersey didn't, and can reasonably complain. It's theoretically possible that congestion pricing could be welfare-reducing if peak demand is inelastic enough. If this were happening, then (1) traffic wouldn't fall much unless the price were raised to extremely high levels, and (2) frequent commuters would be ones most harmed by the policy and would be its most fervent opponents. In New York, we see the opposite: traffic has fallen sharply and frequent commuters are the policy's biggest fans (https://pfnyc.org/news/new-poll-ny-voters-say-congestion-pricing-has-led-to-faster-commutes-and-less-traffic/ https://pfnyc.org/news/new-poll-ny-voters-say-congestion-pri...). Similar things have been seen internationally in other cities; people often initially resist having to pay for something they're used to getting for free, but once it's in place, it's durable and popular because people don't want to go back to traffic jams.
    - nickff 2y ago
      I don’t know much about NYC, much less its transit issues, but it seems like congestion pricing is only marginally popular inside the city, and unpopular in the rest of the state: https://ny1.com/nyc/all-boroughs/traffic_and_transit/2025/03/10/congestion-pricing-disapproval-falls--city-voters-approve https://ny1.com/nyc/all-boroughs/traffic_and_transit/2025/03... Whether congestion pricing is welfare-positive really depends on your utility function. I think rich commuters probably like it, and poorer people who need to drive for work probably hate it. My concerns are more related to political accountability, political incentives, and discrimination against non-voters, all of which exist here.
- bluGill 2y ago
  You have the cause backward. Induced demand is the observation that because people cannot get someplace they already want to go they are going something else instead. The whole point of a city is all the things you can do. If you don't want to go someplace then what are you doing in a city - there are plenty of nice cheap places to live in very rural areas where you can sit in your house going nowhere. Thus cities need to build infrastructure to such that there is no induced demand and the people there can do what they want. Note that I didn't specify what they build. Most cities should be building metro systems not roads.
- janalsncm 2y ago
  Induced demand is only a problem for transportation methods like driving that aren’t scalable. With a metro, you just add more trains and more frequent departure times. Of course such an “ambitious” plan requires political will and less veto power for current residents.

by nickff 2y ago

ameliaquining 2y ago

I'm not sure I understand what you're getting at. "Induced demand" isn't a policy paradigm; it's just the observation that if you make it easier for more people to get somewhere, then more people will go there. Without congestion pricing, the only equilibrium (until you exhaust all demand, which isn't going to happen in hot metro areas) is the one where the roads are congested enough to deter the next marginal person from using them. With congestion pricing, you can choose a different equilibrium without the deadweight loss of people stuck in traffic. The question of how much to invest in infrastructure, and what kinds, can then be addressed separately in whatever way makes sense given local conditions.

nickff 2y ago
Everyone that I’ve ever heard mention ‘induced demand’ with respect to roads does so while advocating against the construction of additional infrastructure capacity for passenger vehicles (cars). This correlation is consistent enough that it does indicate some sort of ‘induced demand paradigm’. I agree that ‘congestion pricing’ does impact traffic, but it does so by changing the cost function, and granting the city government additional revenue from (usually poorer) people who it is not accountable to.
- ameliaquining 2y ago
  Yes, it's definitely the case that a lot of mass transit advocates are confused about this and talk about induced demand in an unproductive way. New York City's congestion pricing scheme was approved at the state level, so it's not true that people living outside the city didn't get a say—though people from New Jersey didn't, and can reasonably complain. It's theoretically possible that congestion pricing could be welfare-reducing if peak demand is inelastic enough. If this were happening, then (1) traffic wouldn't fall much unless the price were raised to extremely high levels, and (2) frequent commuters would be ones most harmed by the policy and would be its most fervent opponents. In New York, we see the opposite: traffic has fallen sharply and frequent commuters are the policy's biggest fans (https://pfnyc.org/news/new-poll-ny-voters-say-congestion-pricing-has-led-to-faster-commutes-and-less-traffic/ https://pfnyc.org/news/new-poll-ny-voters-say-congestion-pri...). Similar things have been seen internationally in other cities; people often initially resist having to pay for something they're used to getting for free, but once it's in place, it's durable and popular because people don't want to go back to traffic jams.
  - nickff 2y ago
    I don’t know much about NYC, much less its transit issues, but it seems like congestion pricing is only marginally popular inside the city, and unpopular in the rest of the state: https://ny1.com/nyc/all-boroughs/traffic_and_transit/2025/03/10/congestion-pricing-disapproval-falls--city-voters-approve https://ny1.com/nyc/all-boroughs/traffic_and_transit/2025/03... Whether congestion pricing is welfare-positive really depends on your utility function. I think rich commuters probably like it, and poorer people who need to drive for work probably hate it. My concerns are more related to political accountability, political incentives, and discrimination against non-voters, all of which exist here.
bluGill 2y ago
You have the cause backward. Induced demand is the observation that because people cannot get someplace they already want to go they are going something else instead. The whole point of a city is all the things you can do. If you don't want to go someplace then what are you doing in a city - there are plenty of nice cheap places to live in very rural areas where you can sit in your house going nowhere. Thus cities need to build infrastructure to such that there is no induced demand and the people there can do what they want. Note that I didn't specify what they build. Most cities should be building metro systems not roads.
janalsncm 2y ago
Induced demand is only a problem for transportation methods like driving that aren’t scalable. With a metro, you just add more trains and more frequent departure times. Of course such an “ambitious” plan requires political will and less veto power for current residents.