If you build it (roads), they (drivers) will come (drive)...

Building roads creates more traffic. That's the conclusion researchers have recently come to. Researchers looked at the data from the last 50 some odd years and found a nearly "perfect one-to-one relationship," between road construction and traffic.

"If a city had increased its road capacity by 10 percent between 1980 and 1990, then the amount of driving in that city went up by 10 percent. If the amount of roads in the same city then went up by 11 percent between 1990 and 2000, the total number of miles driven also went up by 11 percent. It’s like the two figures were moving in perfect lockstep, changing at the same exact rate."

Now, it has been an adage in development circles for some time that if you build for cars and traffic, you will get cars and traffic. But I have never come across a study that has drawn a genuine statistical correlation. So what's causing it?

"The concept is called induced demand, which is economist-speak for when increasing the supply of something (like roads) makes people want that thing even more."

People want to be able to travel as quickly, cheaply and conveniently as they can. That should be a given. But too often we spend a lot of time thinking about the adjectives (quick, cheap and convenient) but not much about that last part. What this research seems to be suggesting is that availability can play just as crucial of a role in decision making as anything. It may well be that people in Los Angeles are willing to sit in traffic simply because they believe it to be the cheapest, quickest, most convenient way to travel - even if it isn't.

If this data is confirmed, it could open up new possibilities for transit development. Some of the options already being considered - like congestion pricing, or market oriented parking pricing - are mentioned in the article linked below. But I can imagine other, more radical ideas. What if, instead of adding lanes to a congested road, you removed a lane and turned it over to a mass transit option like light rail or BRT? It might not do much to reduce the overall level of traffic, but it might induce more people to consider their transit options. And if the only outcome we can rely on is that people are going to max out road capacity whatever we do, maybe should worry less about making drivers happy and focus on making cities better places to live. 


SOURCE: Adam Mann, Wired, http://www.wired.com/2014/06/wuwt-traffic-induced-demand/?mbid=social_gplus