Stress whilst driving sharply increases crash risk and depletes vision and concentration, says RACE

Partly sponsored by petrol giants BP and Castrol, the RACE's research reveals that stress causes drivers to miss up to 20% of traffic signals and creates 'tunnel vision' – an angle of vision of less than 70º – whilst increasing the number of abrupt and erratic moves and sudden accelerations by 17%.

Recalling that distraction at the wheel is the primary cause of fatal road accidents – beyond even alcohol, drugs and speeding – the RACE included a questionnaire in its study answered by over 1,000 motorists.

Of these, 57% say they are thinking about their work while they drive – often because they are running late and panicking, with four in 10 Spanish commuters saying they are regularly late for work because of traffic – and 54% are thinking about family problems whilst at the wheel.

Another 35% worry about money, 33% about their relationships, and 27% about their health.

All this forces up stress levels, causing the 'fight-or-flight' response to kick in with increased heart rate and breathing, nausea and stomach-clenching, and greater sweating, which is usually a self-fulfilling prophecy and makes the person even more wound up.

As a result, those in this frame of mind tend to drive more aggressively and their concentration diminishes by 12%, reducing their reaction times.

Stressed drivers become tired more quickly, causing distractions, since increased muscle tension resulting from the fight-or-flight response means they use up energy more quickly and suffer 80% more fatigue, even on short journeys.

And stress whilst driving means motorists are less likely to even remember their journeys – memory trace retention falls by 66% under prolonged pressure.

Vision during periods of stress whilst driving shrinks to focus solely on the central field, meaning any traffic signals, pedestrians, cars pulling out and other features lateral to this 'tunnel' are missed and motorists pay less attention to their rear-view and wing mirrors.

Of the 1,016 drivers surveyed, a total of 40% say they are unable to forget about their problems and daily hassles when they are behind the wheel – and on short journeys to familiar places, such as the everyday commute, this figure rises to 80%.

This, and the loss of memory of the journey, is due to 'automatic pilot syndrome', and three-quarters of drivers say they have taken a route unthinkingly at least once, completed a drive without remembering anything about it afterwards, or even ended up somewhere that was not their intended destination as they were 'so used to driving there'.

The respondents said the sources of their stress were mainly internal – 47% said it was what was going on in their heads at the time that worried them – although a quarter said external factors like their mobile phones ringing or the radio that caused them anxiety.

The photograph shows footage from a crash on the N-332 highway in Oliva (Valencia province) in October 2015.