Transport for London (TfL) is to run a six-month fleet trial of vehicles fitted with automatic speed limiters.

The trials are in advance of introducing the intelligent speed adaptation (ISA) technology to the fleet and general markets.

Twenty Toyota Prius hybrids from TfL’s fleet of 26 vehicles will be fitted with the ISA devices, which allow drivers to select between an advisory warning or an automatic option where the car is prevented from exceeding the speed limit.

The technology is making use of a new digital speed limit map of London which TfL launched earlier this year.

This is the first time all of London's speed limits have been mapped accurately with regular updates.

It is available on TfL’s website www.tfl.gov.uk/isa

According to a TfL spokesman, driver reaction to the new technology has been overwhelmingly positive.

“Even drivers who were initially sceptical about the use of ISA have been positive about it once they have driven it for several days,” she said.

“The purpose of ISA is not to record or report.

"This is a driver aid and is not intended to take control away from the driver.

"It is estimated that if two thirds of drivers had ISA fitted in advisory mode , the number of casualties on London’s roads would reduce by 10%.”

Drivers have the option to disable the system entirely and have been given training in how to use ISA and the benefits it could bring, before they were introduced.

During the trial TfL will monitor driver behaviour, journey times and the effect that driving within the speed limit has on vehicle emissions.

Following the trial, TfL plans to market the technology to other fleets.

The technology has been developed, supplied and fitted by a Dutch company, Technolution on behalf of TfL, which owns it and has paid for its development at a cost of just under £400,000.

A UK-based supplier is now being sought to manufacturer and supply the market-ready versions.

“This innovative technology could help any driver in London avoid the unnecessary penalties of creeping over the speed limit, and at the same time will save lives,” said Chris Lines, head of TfL's London Road Safety Unit.

"We know the technology works, and now we want to know how drivers in all types of vehicles respond to it.

“ISA is intended as a road safety device, but if Londoners embrace this technology we may well see additional benefits including reduced congestion as a result of collisions and reduced vehicle emissions as drivers adopt a smoother driving style.”

Southwark Council has already expressed an interest in fitting ISA to almost 300 of its vehicles.

Councillor Jeff Hook, executive member for environment at Southwark Council, said: “This technology could revolutionise the way we keep our roads safer in Southwark, and that's why we're really interested in this trial, and if it's successful we hope to kit out our entire fleet of nearly 300 vehicles as soon as funding allows.”

However, Andrew Howard, head of road safety at the AA, offered a word of caution: “Drivers are divided in their views of intelligent speed adaptation - some hate it, some want it,” he said.

 

 

How ISA works
On advisory setting, the intelligent speed adaptation technology uses a typical satellite navigation system with a digital speed limit map loaded into it.

This is used to accurately determine the road and the speed limit the car is on.

If the driver selects the ISA to automatically restrict the speed of the vehicle, limiting equipment is used that interacts with the engine to keep the vehicle below the speed limit.

This involves cutting out, or “hijacking” the electrical signal that goes from the accelerator to the fuel supply.