BBC News Online: Health

Staring ahead 'raises crash risk'

Endlessly repeating images, even moving ones, like white lines and trees lining the road, can cause the brain to switch off in a process known as "motion adaptation".

Once motion adaptation has taken place, drivers are more likely to subconsciously put their foot down, driving on average approximately five miles per hour faster.

The research was published in the American Psychological Association's Journal of Experimental Psychology.

The research team placed 18 experienced drivers in a realistic driving simulator, which included a wide field of view, rising and falling engine noise, and even feedback from the steering wheel.

After five minutes of driving along a straight, empty road, they were asked to perform a simple overtaking manoeuvre on a vehicle travelling in the same direction.

The study found that, after five minutes, the drivers started the overtake up to half a second later than a similar manoeuvre completed at the start of the exercise.

This substantially increased the risk of "clipping" the rear end of the car in front while pulling out.

When given a section of winding country road to complete before the overtake, there was no impairment.

'Fatal error'

Dr Rob Gray, who led the research, explained how the brain reacts when confronted with objects moving in a repetitive fashion.

He said: "Motion adaptation - a change in the motion detecting cells in your brain produced by prolonged viewing of moving objects - can occur when driving on a straight empty road.

"This can have detrimental effects on visually guided motor actions such as overtaking another car and can lead to a fatal error."

The solution, he says, is for drivers to look away from the road more often when engaged on long, straight sections, with perhaps car manufacturers creating dashboard displays which occasionally briefly attract the attention of the driver.