Wednesday, January 22, 2020

The law of induced demand





































Londoners get around by car. Oh, there's a bus service and there was a discussion for a Light Rapid Transit system. The LRT idea never took flight. Very early on it was replaced with the promise of an almost as good, but a some what less expensive, Bus Rapid Transit system.

On the drawing board, the BRT system was going to serve the entire city. But before a penny was spent, two big segments of the BRT system were scrapped. Then funding became a question.

What I don't understand is why, when a heavily traveled street like Southdale Rd. W., shown, is upgraded, some thing is not done to widen the roadway with the goal of providing for even a crude BRT system. But the road is widen for cars and cars fill the new, wide road. It is the law of induced demand.

Building roads alone does not solve traffic congestion problems in the long term. Build it, widen it, add more lanes and drivers will be attracted to the new open roadway. The result? Traffic will increase. The British government did a study showing that increasing traffic capacity coaxes people to drive more – a lot more. Fully half of any driving-time savings resulting from the opening of a new roadway is quickly lost. The oh-so-costly benefits will all be negated within a decade.

1 comment:

William Kendall said...

We've had a bus transitway for a long time, and more recently have been upgrading our LRT from a one line trial to a second line that'll wind up getting expanded.

That second line has been having some growing pains.