Professor Stephen Robinson said the effects of physical vibration on drivers were not well understood, despite growing evidence that vibration contributes to feelings of sleepiness.

“We know 1 in 5 Australians have fallen asleep at the wheel and we know that drowsy driving is a significant issue for road safety,” Robinson said.

“When you’re tired, it doesn’t take much to start nodding off and we’ve found that the gentle vibrations made by car seats as you drive can lull your brain and body.

“Our study shows steady vibrations at low frequencies - the kind we experience when driving cars and trucks - progressively induce sleepiness even among people who are well rested and healthy.

“From 15 minutes of getting in the car, drowsiness has already begun to take hold. In half an hour, it’s making a significant impact on your ability to stay concentrated and alert.

“To improve road safety, we hope that future car seat designs can build in features that disrupt this lulling effect and fight vibration-induced sleepiness.”