"The fact that people come when capacity is improved shows that you're lessening the load on other roads!" False. There's a concept called Induced Demand. (htt

"The fact that people come when capacity is improved shows that you're lessening the load on other roads!" False. There's a concept called Induced Demand. (http://en.wikipedia.org/wiki/Induced_demand http://en.wikipedia.org/wiki/Induced_demand) There are many drivers who stay off the roads because the cost of congestion is too high. For instance, people who won't take a given trip if it takes longer than 20 minutes. By increasing road capacity the trip time goes down to 15 minutes. This induces demand from the crowd that desires <20-minute trips. As they join the crowds on the road, they bring congestion back to its equilibrium level of a 20-minute trip.