David Crawford finds out how drivers who flout the speed limit could be reined in by cars that 'know' how fast they are travelling

Over the next few months, 20 volunteer motorists will be testing revolutionary speed-control technology as they drive around Leicester and south-west Leicestershire. They are taking part in the UK's first major trial of intelligent speed adaptation (ISA) technology, which aims to cut road accidents and could make speed cameras redundant.

Running the £1.9m trial for the Department for Transport (DfT) are the University of Leeds Institute for Transport Studies (ITS) and the Nuneaton-based Motor Industry Research Association (Mira). They have equipped a fleet of Skoda Fabia 1.4l estates with a speed-tracking kit.

A GPS receiver, combined with speed-derived dead reckoning, positions each car accurately on a digital road map, which is overlaid with speed limit data and stored in a navigation computer. A second computer - the vehicle control unit (VCU) - compares the car's speed with the maximum permissible at that point, and interacts automatically with the throttle and brakes to keep it within the limit.

The driver can override the ISA - for example, to accelerate out of danger - by pressing a button on the steering wheel. When the speed drops back below the limit, the ISA automatically re-engages; alternatively, the driver can press a second button.

The system is designed to read the road ahead, so that the car brakes gradually when moving from a 60mph zone to a 30mph one. At the end of each journey, it automatically sends the project team an SMS message, to relay trip data and confirm that the system is working.

The team chose the Fabia as a typical, small, family car with a throttle-by-wire engine system, on which the ISA software could act. The internal kit is tucked away behind the glove compartment and in the boot's spare-wheel well, to make the ISA seem standard equipment and avoid drivers feeling like guinea pigs. (A GPS aerial replaces the original FM one.)

A digital display in the centre of the instrument panel keeps the driver informed of local speed limits. An extra jingle warns as these change, while a vibrator mounted on the accelerator pedal responds if the driver depresses it further than is needed to maintain the correct vehicle speed. (The VCU is programmed to take account of the amounts of throttle needed when on a steep gradient.)

The volunteers are a mix of private motorists and local authority employees, who drive fleet cars. For the first month of the six-month trial, they drive with the ISA switched off, to allow the project team to monitor their normal behaviour. It then operates for four months, before being switched off again to show if and how behaviour has changed.

Leicester is part of a two-centre project, with results just emerging from a prior trial in the more densely congested conditions of Leeds. Professor Oliver Carsten, chair of transport safety at Leeds University, says: "We are finding that drivers make more use of the override where there are defined speed limits, for example, on motorways and 30mph roads. Overall, they have ended up with positive feelings about ISA."

David Stevens used an ISA car. "ISA increased my awareness of speed limits", he says. "I learnt to look ahead for them, because the automatic braking when dropping down from, say, 50mph to 30mph was initially disconcerting." He used the override about once a week on average. He would be happy to see the system introduced across the board, as a way of dealing with "really stupid" drivers.

Mira's Richard Adams estimates that the on-board equipment could be in commercial production by 2013, if the trial results prove satisfactory. Drivers could then be encouraged to use it on a voluntary basis.

The DfT stresses that there are no Government plans to make ISA compulsory in the UK, although the European Commission, which supports multinational research on speed control, has indicated that it will consider introducing regulation if industry initiatives prove inadequate. Adams sees the insurance sector industry as a key driver, with lower premiums offered to ISA-equipped drivers.

The EC is also interested in the potential environmental benefits. ISA trials in Sweden and the Netherlands predict falls in emissions of between 6 and 11 per cent as the result of more considered driving.

The writer is a contributing editor of 'Intelligent Transport Systems International'

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