THE FUTURE OF CITIES IS CARLESS:

Research to be presented at the Royal Economic Society's annual conference later this month found that traffic accidents have fallen in the capital by an astonishing 40% since 2003. The work is the first study of its kind and is likely to be examined closely by other cities that have flirted with the idea of imposing a similar charge.

The £5 charge was hailed as a triumph of economics that forced those contributing to congestion to pay. The resulting fall in traffic confirmed predictions that the charge - increased to £8, then £11.50 - could change motorists' behaviour.

With fewer cars on the roads in central London, motorists can go faster. This could have increased the risk of accidents. However, the research team led by Professor Colin Green of the economics department at Lancaster University found that the charge has instead resulted in a substantial reduction in the number of accidents and fewer fatalities.

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