A dashboard finger scanner could prevent thousands of car injuries each year by fine-tuning crash restraint systems to a passenger’s bone density.

The ultrasound scanner, developed by researchers at Cranfield Impact Research Centre (CIRC) and Nissan Technical Centre Europe, both in the UK, assesses an individual’s tolerance to injury, allowing a vehicle’s onboard computer to adjust the force applied by their seatbelt and airbag accordingly.

“It would need to be used each time the car’s ignition was switched on, before the driver was able to move off,” says CIRC’s technical director, Roger Hardy.

“This would then feed into the restraint system – part of a processing unit in the car – in addition to what is routinely used to detect the conditions for firing airbags and controlling the seatbelt operating characteristics,” he adds.

Smart seatbelts can already let out slack when under excessive strain, to prevent a passenger suffering injury such as rib and sternum fracture. But not everyone can withstand the same amount of force and those with brittle bones are particularly at risk.

The ultrasound sensor tries to determine how much strain a passenger can take by firing harmless sound pulses through a finger and measuring the amount of time they take to pass through. This reveals the density of the bone, allowing an onboard computer to configure the smart seatbelt to prevent injury. It could also alter air bag settings, perhaps softening the cushioning slightly if the passenger seems especially frail.

The system should particularly benefit older drivers and other passengers who typically suffer more injuries in minor crashes, says Richard Frampton at the Ergonomics and Safety Research Institute at Loughborough University, UK, who helped develop the system.

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