Why Expanding Roads Fails to Reduce Traffic Congestion
6 hours ago
- #urban-planning
- #economics
- #traffic-congestion
- Expanding roads does not reduce traffic congestion due to induced demand.
- The Fundamental Law of Road Congestion states that peak-hour traffic rises to meet maximum capacity.
- Research by Duranton and Turner (2011) shows a 1% increase in lane kilometers leads to a 1.03% increase in vehicle-kilometers traveled (VKT).
- Sources of increased VKT include commercial traffic (20-30%), individual behavior (9-39%), and minimal impact from migration or traffic diversion.
- Public transit expansion does not reduce VKT, as induced demand fills any freed road space.
- Congestion pricing is the only proven solution to reduce traffic congestion by internalizing external costs.
- New York City's congestion pricing has successfully reduced commute times and pollution.