IN 1868 the world’s first traffic light was installed outside the Houses of Parliament. The gas-lit signal controlled the flow of London carriages—at least for a few weeks. For, soon enough, the gas ignited. The resulting explosion knocked the helmet off a policeman’s head, and left him badly burned.
Efforts to ease congestion no longer literally blow up in your face, but recent schemes have run into trouble, too. In 2003 Ken Livingstone, then London’s mayor, introduced a congestion-charging zone (CCZ). Motorists pay up to £11.50 a day ($15.20) to drive into the centre of the city. Since 2000 the number of cars entering central London has fallen by nearly a quarter.
But congestion is rising again (see chart 1), a result of vans and taxis clocking up more miles within the zone, as well as new lanes for buses and Lycra-clad commuters.
Read more: How and why road-pricing will happen