Transport for London (TfL) plans a six-month trial of the Intelligent Speed Adaptation (ISA) technology starting this summer, to ease traffic congestion and bolster road safety.

ISA uses satellite tracking and a digital road map to detect the local speed limit of the vehicle. The device has an automatic mode and advisory setting.

In advisory setting, the driver is informed of the limit and told whether he is complying. A “smiley face” appears on the unit if the driver is obeying the limit. It frowns if he goes too fast.

In the automatic mode, system automatically decreases the speed of vehicle, if the driver fails to reduce the speed, after passing the lower speed limit sign mark.

However, the drivers of vehicles with ISA will be able to select an option that prevents from accelerating over the limit.

TfL’s Road Safety Unit head Chris Lines said: “This innovative technology could help any driver in London to avoid the unnecessary penalties of creeping over the speed limit and at the same time will save lives – the times online reported.

TfL’s trial involves a London bus, a licensed taxi and 20 cars driven by road engineers, traffic managers and highway inspectors. However, Southwark Council has expressed an interest in fitting ISA to more than 300 of its vehicles.

Results of the trial will be published in spring, when the technology will be made available to other organisations.

If the trial gives successful results such as clear safety and environmental benefits, the bus companies and taxi operators could either be obliged to equip their vehicles with ISA or be given incentives to do so.

The road casualties in the capital could be reduced by 10%, if this technology is used by two thirds of London drivers, as per the estimates by the TfL.