Extendable bumpers could be used by convoys of 鈥渋ntelligent vehicles鈥 to maintain safe distances when normal communications fail, researchers say.
Simulations suggest that bumpers that expand pneumatically to touch the car ahead could help keep the convoy together safely in an emergency.
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Researchers are interested in intelligent vehicles capable of organising themselves into tight platoons to reduce congestion, save fuel and cut down on accidents. Several prototype automated control systems have been demonstrated in recent years.
But these all present new safety challenges, says Alasdair Renfrew, an intelligent transport researcher at Manchester University, UK. 鈥淎lthough the overall benefits, including the potential for greater safety, are considerable,鈥 he told New Scientist, 鈥渢he consequences of a system failure are potentially quite severe.鈥
Lost in communication
An automated platoon requires each car to communicate with those nearby, and sometimes with roadside systems too. If these communications become disrupted, the situation may rapidly become too complex for a human driver to deal with. Renfrew and colleagues Aurelio Gonzalez-Villasenor and Paul Brunn think an intelligent, extendable bumper could be the answer.
They used computer models to test how well cars equipped with an extendable bumper at the front using a combination of hydraulics and pneumatics might cope when communications fail.
Sensors in the bumper would allow a car to determine what the one in front was doing and react quickly. Measuring compression of the bumper would track the relative speed and acceleration of the car ahead.
鈥淪imulation results show that, with this system, vehicles can be brought into contact at a rate of up to 3.5 metres per second (8 miles per hour) without exceeding passenger comfort constraints,鈥 Gonzalez-Villasenor told New Scientist. 鈥淭hen the vehicles are maintained safely in contact using measurements from the device itself.鈥
As long as the lead car followed speed limits and drove sensibly, the convoy could stay together. Simulations with varying wind conditions and gradients showed up to 20 cars could safely convoy in this way. 鈥淲e consider that this might ease the legal challenges associated with 鈥榓utomatic highways鈥,鈥 says Gonzalez-Villasenor.
Small scale
The team are currently testing a small scale prototype of the bumper to determine the best control strategies.
The system could well address an important concern, says Richard Hall, who is researching the way smart vehicles impact driver behaviour at Southampton University, UK (see Watchful car monitors drivers every move).
鈥淸Safety] is usually one of the most difficult parts of the process,鈥 Hall told New Scientist. 鈥淧eople have great ideas but assessing and designing safety is more difficult. Safety concerns need to be addressed if it is to get further, perhaps this system will be able to help.鈥
The Manchester team鈥檚 work won Best Scientific Paper at the Intelligent Transport Systems World Congress and Exhibition in London in October 2006 (see Clever cars shine at intelligent transport conference).
