The Motorfit system, which utilises a computer database, has been on trial since August and could help identify cars used in a variety of crimes, particularly in hit-and-run cases and child abductions.
It resulted from an investigation four years ago, when police in Weymouth, Dorset, had difficulty tracing a driver who was repeatedly trying to entice young children into his car. The descriptions given of the vehicle were partial and trying to track it down meant ploughing through brochures and colour charts.
The officer dealing with the investigation, Simon Grantham, then a community beat constable and now a sergeant, felt there must be a better way. 'I realised that there was no vehicle identification index of any type available to the police; we had to slog through car brochures. I thought I might see if we could do something about it,' he said.
His initial idea for a database of car types won him and Dorset Police a pounds 27,000 Home Office research grant. It progressed through Southampton University to the Home Office and the Crown Prosecution Service, which established guidelines for use.
Motorfit can be used to help assault victims: suppose a woman has been dragged into a car, raped and left by the roadside. When interviewed, she may only have a partial recollection of the colour and a view of the car rear; perhaps the shape and colour of the bumper remain in her mind.
These details can be input into the Motorfit system, which has 250 different indices covering body types, interior designs and styles all rated according to strength of recollection. The computer offers a choice of 18 colours, broken down into shades and giving a total of 2,600 combinations.
Once the profile is entered, the computer matches the detail against its memory bank of 2,500 cars - all makes, models and versions sold in the United Kingdom over the past 20 years. It then ranks all 2,500 in order of similarity to the profile and photographs of the nine closest matches are displayed for the witness to select the one fitting that person's recollection; if it is not among the first nine, the next closest nine are displayed. As soon as a car is chosen, police can concentrate their search. They can rapidly issue a public appeal based on a Motorfit picture or check against the police national computer.
The system is also being tested in Lancashire and by the Metropolitan Police in London, where Inspector Mick O'Brien said: 'It has potentially great benefit in fail-to-stop traffic accidents and is certainly an improvement on looking through brochures.'