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Traffic is subject to induced demand. Roads fill until traffic is high enough to convince people not to drive (either taking fewer trips or going via not car).
by Arainach 3y ago
Traffic is subject to induced demand. Roads fill until traffic is high enough to convince people not to drive (either taking fewer trips or going via not car). If you build more roads, more people will drive until traffic is bad enough to get them not to, etc. etc.
We have nearly a century of data on this. It was observed when Robert Moses tried to build more parkways in New York, it was true in Texas and LA, it was true everywhere.
"Traffic is already bad" is a common NIMBY line in my area, but traffic will always be bad with sufficient population. Building more roads will not change that.
- didntcheck 3y agoWhy doesn't this apply to public transport too? Is there no point running more buses or trains because they'd just fill up again? And shouldn't this mean all roads should be packed all the time, rather than having many which are always fairly quiet, even in rush hour?
- Arainach 3y agoThe capacity and throughout of public transit is dramatically higher and scales far better, so it's harder to hit limits and cheaper to scale them up. Yes, it's technically affected - both in the "if you build it they will come" sense and that if transit becomes sufficiently congested people will change their transportation behavior - but cars have more liquidity and hit traffic limits much easier.