If you cross our road, you can access five primary schools, two nurseries, a playground, and a home for elderly mentally infirm people. We used to have the best speed bumps in London: elegant little terracotta tables with gently sloping tarmac either side. Ninety-nine per cent of cars slowed down. Boy racers did predictable damage to their undercarriages. Nobody got killed.
The boy racers got together and lobbied the local council. They claimed that their civil liberties (the right to hit the accelerator when travelling down a residential road) were at stake. They presented a portfolio of “evidence,” downloaded from a US website calling itself “The rational motorists' guide to opposing speed bumps and other traffic obstruction strategies.” Apparently, speed bumps cause up to 250 000 deaths from sudden cardiac arrest, and hundreds of deaths from house fires. And that's not to mention all the bandits who escape while police cars are held up.
The original council committee was easily bought, since the boy racer evidence (despite the absence of a reference list) came with an American logo and was generously peppered with statistics. The council established what it called a “common sense” policy of removing speed bumps and then asking local residents if they minded. And when residents did mind, the council found it had run out of money.
The Medline database lists three meta-analyses of empirical trials of traffic calming measures. The largest, from the Institute of Transport Economics in Oslo, reviewed 33 primary studies and found that, overall, area-wide urban traffic calming schemes reduced the number of injury-related accidents by between 10% and 25%, with no discernible change in sudden cardiac deaths or deaths from house fires.
I took this evidence to a second council meeting. The chairman was unimpressed. He explained that the procedure on reinstating road humps was simple and non-negotiable: one vote for the residents of the road, one for the councillor for transport, one for the emergency services, and one for himself. Nobody could be required to read the research evidence before voting.
The boy racers are now lobbying traffic police—a group of young men self-selected for their enjoyment of exceeding the speed limit. So far, fortunately, only a cat has been killed.