Airbags for pedestrians

An airbag system to protect pedestrians is set to be unveiled later this year following UK trials.

AN airbag system to protect pedestrians is set to be unveiled later this year following UK trials.

Two airbags, fitted to a car’s bonnet and windscreen, are designed to inflate moments before the vehicle hits a pedestrian to reduce the risk of severe injury.The project, known as Advanced Protection for Vulnerable Road Users (APVRU), has been sponsored by the government and led by the Transport ResearchLaboratory.

Bryan Chinn, head of vehicle safety systems at TRL, said engineers are now perfecting the complex sensor system needed to identify pedestrians in danger and deploy the airbags, following human trials held over the past few months.

Around 900 pedestrians are killed each year on the UK’s roads, while a further 39,000 are injured. The European Enhanced Vehicle- safety Committee (EEVC) has called on car manufacturers to improve the design of vehicles by 2005, to help reduce the number of deaths and serious injuries.

So researchers are attempting to develop more pedestrian-friendly technologies, including bumpers filled with shock absorbing liquids, which are being designed by a team at Manchester University.

The TRL system is based on an infrared camera, which identifies whether or not an object in front of a car is a pedestrian. A radar then decides if the pedestrian is indanger of being hit by the car, and if there is a real threat of collision the system deploys the airbags.

The biggest challenge has been ensuring the sensors fire the airbags exactly when needed, said Chinn. Too early and the airbag may deflate before impact; too late and the pedestrian might be injured further or knocked into incoming traffic.

Infrared detectors could also be fooled by a car engine’s heat or even reflected sunlight, so special algorithms had to be designed to recognise a pedestrian’s shape.

The researchers are developing a method of protecting the sensors to prevent them from being obscured by mud. The team has also yet to decide exactly where on the car the sensors should be placed, to ensure maximum accuracy without interfering with the car’s design.

Other APVRU partners include Jaguar, infrared specialist IRISYS and the University of Surrey. During recent trials of the detection system, volunteers ran towards the sensors, to ensure they could be identified, and the results were said to be promising. A prototype system is now being built.