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I am a huge proponent of better public transit but I think pointing out induced demand and saying extra lanes has no benefits is misleading. If four lanes can

I am a huge proponent of better public transit but I think pointing out induced demand and saying extra lanes has no benefits is misleading. If four lanes can handle 10,000 cars an hour at 45mph and six lanes can handle 15,000 cars an hour at 45mph then induced demand pointer-outers will point out that this doesn't help the traffic. And this is true! But clearly if the goal is for a city to get as much cars through as possible + make as many houses in the range of distance that can commute this is a plus. This creates lots of problems with carbon waste and sprawl but I think looking at the traffic issue alone doesn't capture the full picture. It's like telling a restaurant that has an average wait time of 20 minutes that if they build 50% more tables and improve their wait staff that they will still have 20 minute wait times on Friday. This is true - but the wait time being held constant while drastically increasing capacity accomplishes the stated goals. And I have a hunch a lot of this criticism probably comes from a place of wealthier people who live within a very short distance of their place of work.

eppp 5y ago
Is that ever the stated goal or complaint? Anecdotally of course, but I have never heard anyone in traffic wish that the road could carry even more cars at a higher rate. They want there to be less traffic. Building more lanes never accomplishes this. Take Atlanta for instance, something that would actually help traffic would be to build bypasses with no on ramps that circle the city. Every time they build a new loop so that truck traffic can bypass, more houses are built near that loop.
- zamadatix 5y ago
  It's hard to separate the two in casual conversation if you're not explicitly intending to. E.g. if someone says "it's a bad time to drive into the city I should do it later" it's easy to interpret that as "there is too much traffic there would need to be less" but it's the exact use case adding another lane allows, more cars decide to come in until the pressure is enough that for additional cars "it's a bad time...". Same with the houses, they instantly popup because there is now more capacity to take people in where there wasn't before. Clearly you can't build enough roads to satisfy this relationship to the point the physical distance the car can reasonably travel in a day is the limiter instead of the number of cars that can make it should there be a road available to fit them which is why it's not an answer for congestion in large cities but it can be the answer to capacity into target cities (barring enough support for more efficient means like mass transport).
- handmodel 5y ago
  I 100% agree that the person in the car is only thinking of themselves and wants traffic time reduced. But I don't think that is the goal of the people building the highways. They are thinking of how to maximize the economic output of a city + connect people to areas they currently have no access to. In your example it is a huge win for the city that new houses can be built in areas that have quick access to the highway and therefore the city. You (the incumbent) may not benefit but the number of people that now have a similarly nice experience to the people that already live close enough to the city to have access will increase.

eppp 5y ago

Is that ever the stated goal or complaint? Anecdotally of course, but I have never heard anyone in traffic wish that the road could carry even more cars at a higher rate. They want there to be less traffic. Building more lanes never accomplishes this. Take Atlanta for instance, something that would actually help traffic would be to build bypasses with no on ramps that circle the city. Every time they build a new loop so that truck traffic can bypass, more houses are built near that loop.

zamadatix 5y ago
It's hard to separate the two in casual conversation if you're not explicitly intending to. E.g. if someone says "it's a bad time to drive into the city I should do it later" it's easy to interpret that as "there is too much traffic there would need to be less" but it's the exact use case adding another lane allows, more cars decide to come in until the pressure is enough that for additional cars "it's a bad time...". Same with the houses, they instantly popup because there is now more capacity to take people in where there wasn't before. Clearly you can't build enough roads to satisfy this relationship to the point the physical distance the car can reasonably travel in a day is the limiter instead of the number of cars that can make it should there be a road available to fit them which is why it's not an answer for congestion in large cities but it can be the answer to capacity into target cities (barring enough support for more efficient means like mass transport).
handmodel 5y ago
I 100% agree that the person in the car is only thinking of themselves and wants traffic time reduced. But I don't think that is the goal of the people building the highways. They are thinking of how to maximize the economic output of a city + connect people to areas they currently have no access to. In your example it is a huge win for the city that new houses can be built in areas that have quick access to the highway and therefore the city. You (the incumbent) may not benefit but the number of people that now have a similarly nice experience to the people that already live close enough to the city to have access will increase.