New regulations for PSV's

Automatic speed limiters could be fitted to hundreds of taxis, buses and council vehicles to prevent them from breaking the speed limit.

A major trial by Transport for London will see the technology, which is called Intelligent Speed Asaptation (ISA), tested throughout London this summer.

The device works using satellite tracking and a digital road map to detect the road's speed limit. It then prevents the driver from being able to accelerate once the speed limit has been reached, and automatically slows the vehicle if the driver fails to slow down on entering a lower limit zone.

As well as the automatic limiting, the device also features an advisory setting, which is less intrusive and simply uses audio warnings to inform the driver of the speed limits and whether the they are keeping within them.

If successful, the technology could become available for private motorists as early as next year, a move which has concerned motoring organisations.

Transport for London's six-month trial will include a London bus, taxi and 20 cars from road engineers, traffic managers and highway maintenance. They claim that if two-thirds of London's drivers used the devices, the number of road casualties in the capital could be reduced by up to 10 percent.