4 ms·

If you expand a road, there will be greater usage because demand soaks up supply. However, cars are big and takes up a lot of space, especially since people re

by kiba 5y ago

If you expand a road, there will be greater usage because demand soaks up supply. However, cars are big and takes up a lot of space, especially since people regularly drive sedans that seat only one individual with max capacity for four to five people. This requires a lot of space to support cars. Of course, you can continue to expand roads. Problem with that idea is that the roads displace other uses of land such as homes and businesses. Roads increase utility of cars, for sure, but that comes at the expense of everything else.

fearfulofview4 5y ago
Don't forget bankrupting municipalities and states by misallocating untold sums of money toward road construction and maintenance and not investment in human capital: schools, healthcare, and other high-ROI public goods.
burlesona 5y ago
Sedans? Try 5000lb, 7-8 passenger SUVs.
acdha 5y ago
It’s easy for people to forget just how spatially inefficient cars are because we’re so used to 30-40% of city space being dedicated to roads and storage. We saw a dramatic example of this next to the bike path I ride to daycare/work: hundreds of new apartments, restaurants & other retail shops, outdoor public spaces, etc. next to a subway station. This was just part of a retail parking lot which broke 50% usage _maybe_ a couple of times a year. The number of people using the space when up by at least an order of magnitude and it’s a lot more consistent economic activity.
thereisnospork 5y ago
> If you expand a road, there will be greater usage because demand soaks up supply. This can only occur when there is sufficient latent demand, or phrased differently, the supply of roads (and sufficiently fungible transit modes) is so insufficient that that moderate increases in supply do not create a surplus. This lack of surplus (traffic) representing an economic inefficiency which it can only be desirable to reduce[0]. What is stupifying is how 'induced demand' (read: building more roads will cause more people to perform economic activities facilitated by transit) is contorted into an argument against building roads. [0]Until such point that traffic inefficiency is in equilibrium with others. e.g. I can't see Manhattan widening 5th ave anytime soon, but most of America isn't pressed for real estate.
- danhor 5y ago
  The article points out that more supply of roads also leads to less density, which requires more driving, which requires more roads. This is not the short-term induced latency but for sure a part of it and part of why katy highway exists.
  - thereisnospork 5y ago
    Lets look at the null position and agree that induced demand is bad and we shouldn't build more roads, which means the question becomes: How many roads should we be tearing up[0], and how do we know when we've torn up the correct amount? Since we a. clearly aren't at the optimal amount of roads[1], and b. induced demand argues that we shouldn't be building more. [0]A clearly nonsensical position.
    - danhor 5y ago
      > A clearly nonsensical position. I don't find it nonsensical at all. My city is actively planning to reduce the amount of normal roads in the city center and introducing more & better bicycle lanes. This is very much needed, since while the central crossing does have (some) gutter bike lanes leading to it, it comes close to suicide to use them. Accordingly, no one does and many use the sidewalks that are already too small for comfort without bikes (the city is in a bad spot there, because it's very space constrained in that place. The roads are badly overloaded in the center and no lanes can be added due to the lack of space). A nearby larger city would be well advised to remove traffic & lanes from central locations and allow more bike paths and crucially allow expanding the badly overloaded subways with trams (and dedicated tram ways) near the center. Due to various factors, there's no real option to use more tunnels. They have been routinely over the limits for particulate matter and were successfully sued over it. Now, roads outside of cities are complicated. The larger ones usually can't be easily reduced, but eat a lot of maintenance costs that could go towards higher capacity options (rail). Looking at https://en.wikipedia.org/wiki/Braess%27s_paradox https://en.wikipedia.org/wiki/Braess%27s_paradox and carefully analyzing existing roads may also make sense. In general, car based travel costs society the most per mile by far. Introducing measures like tolls & car-free cities as well as making alternatives more attractive with shifted spending may reduce demand and thus enable tearing down roads. The question hinges on a false dichotomy that the only solution to demand is more roads, which is part of what this article is arguing against. Edit: An obvious but politically hard solution to overloaded roads is encouraging higher density.
throwawaysea 5y ago
> If you expand a road, there will be greater usage because demand soaks up supply. Only up to a limit, as I mentioned. They won’t keep “soaking up” supply. People are not looking to drive 24/7. They are looking to reach destinations and spend time there. > Of course, you can continue to expand roads. Problem with that idea is that the roads displace other uses of land such as homes and businesses. This seems like a vague argument. Road space displaces other uses marginally. If your population were held equal, then you can build more roads, displace some amount of other uses, and the increased traffic from those displaced wouldn’t be nearly as much as the extra traffic capacity the road provides. If your population increases or usage patterns change, then it is simply “latent” demand that is being met, since there’s an appetite for more travel throughout and increased speeds and all the utility that brings. All of this applies to anything that we can model with supply and demand, including bike lanes.

by kiba 5y ago

fearfulofview4 5y ago

Don't forget bankrupting municipalities and states by misallocating untold sums of money toward road construction and maintenance and not investment in human capital: schools, healthcare, and other high-ROI public goods.

burlesona 5y ago

Sedans? Try 5000lb, 7-8 passenger SUVs.

acdha 5y ago

It’s easy for people to forget just how spatially inefficient cars are because we’re so used to 30-40% of city space being dedicated to roads and storage. We saw a dramatic example of this next to the bike path I ride to daycare/work: hundreds of new apartments, restaurants & other retail shops, outdoor public spaces, etc. next to a subway station. This was just part of a retail parking lot which broke 50% usage _maybe_ a couple of times a year. The number of people using the space when up by at least an order of magnitude and it’s a lot more consistent economic activity.

thereisnospork 5y ago

> If you expand a road, there will be greater usage because demand soaks up supply. This can only occur when there is sufficient latent demand, or phrased differently, the supply of roads (and sufficiently fungible transit modes) is so insufficient that that moderate increases in supply do not create a surplus. This lack of surplus (traffic) representing an economic inefficiency which it can only be desirable to reduce[0]. What is stupifying is how 'induced demand' (read: building more roads will cause more people to perform economic activities facilitated by transit) is contorted into an argument against building roads. [0]Until such point that traffic inefficiency is in equilibrium with others. e.g. I can't see Manhattan widening 5th ave anytime soon, but most of America isn't pressed for real estate.

danhor 5y ago
The article points out that more supply of roads also leads to less density, which requires more driving, which requires more roads. This is not the short-term induced latency but for sure a part of it and part of why katy highway exists.
- thereisnospork 5y ago
  Lets look at the null position and agree that induced demand is bad and we shouldn't build more roads, which means the question becomes: How many roads should we be tearing up[0], and how do we know when we've torn up the correct amount? Since we a. clearly aren't at the optimal amount of roads[1], and b. induced demand argues that we shouldn't be building more. [0]A clearly nonsensical position.
  - danhor 5y ago
    > A clearly nonsensical position. I don't find it nonsensical at all. My city is actively planning to reduce the amount of normal roads in the city center and introducing more & better bicycle lanes. This is very much needed, since while the central crossing does have (some) gutter bike lanes leading to it, it comes close to suicide to use them. Accordingly, no one does and many use the sidewalks that are already too small for comfort without bikes (the city is in a bad spot there, because it's very space constrained in that place. The roads are badly overloaded in the center and no lanes can be added due to the lack of space). A nearby larger city would be well advised to remove traffic & lanes from central locations and allow more bike paths and crucially allow expanding the badly overloaded subways with trams (and dedicated tram ways) near the center. Due to various factors, there's no real option to use more tunnels. They have been routinely over the limits for particulate matter and were successfully sued over it. Now, roads outside of cities are complicated. The larger ones usually can't be easily reduced, but eat a lot of maintenance costs that could go towards higher capacity options (rail). Looking at https://en.wikipedia.org/wiki/Braess%27s_paradox https://en.wikipedia.org/wiki/Braess%27s_paradox and carefully analyzing existing roads may also make sense. In general, car based travel costs society the most per mile by far. Introducing measures like tolls & car-free cities as well as making alternatives more attractive with shifted spending may reduce demand and thus enable tearing down roads. The question hinges on a false dichotomy that the only solution to demand is more roads, which is part of what this article is arguing against. Edit: An obvious but politically hard solution to overloaded roads is encouraging higher density.

throwawaysea 5y ago

> If you expand a road, there will be greater usage because demand soaks up supply. Only up to a limit, as I mentioned. They won’t keep “soaking up” supply. People are not looking to drive 24/7. They are looking to reach destinations and spend time there. > Of course, you can continue to expand roads. Problem with that idea is that the roads displace other uses of land such as homes and businesses. This seems like a vague argument. Road space displaces other uses marginally. If your population were held equal, then you can build more roads, displace some amount of other uses, and the increased traffic from those displaced wouldn’t be nearly as much as the extra traffic capacity the road provides. If your population increases or usage patterns change, then it is simply “latent” demand that is being met, since there’s an appetite for more travel throughout and increased speeds and all the utility that brings. All of this applies to anything that we can model with supply and demand, including bike lanes.