If you build it, they will come

It amazes me that still, in 2009, there are people who think road congestion can be fixed by building more roads. The idea that demand is inelastic, or elastic within the limits of what can be satisfied without completely destroying the character of our landscape and towns, has virtually no support any more among traffic professionals.

In the 17th Century and  both proposed ambitious schemes to redraw the streets of London after the great fire. These plans foundered due to property interests. Property owners were not willing to allow their assets to be bought at whatever price in order to redraw the map; they wanted to keep their property, rebuild, and continue trading as soon as possible. Only once since then has London suffered comparably cataclysmic destruction, and again rebuilding was on the old lines.

And even if we had been able to redraw the streets, what then? Los Angeles is virtually built around the car, its network of freeways is the most extensive of any conurbation in the world, and yet so is its traffic problem. The number of journeys and average distance travelled consistently grows to fill any increased provision. Where in Britain could you build roads this wide? And yet they are full to capacity and stationary for an hour or more every day.

All the evidence points to a single conclusion: building more roads generates more traffic. That's not a reason not to build roads, but it is a reason why building roads will not - cannot - fix traffic problems.