Drowsy Drivers Asleep at the wheel

The Department of Transport’s Think! campaign has highlighted the dangers of drowsy drivers. A two-year investigation based on accidents on the M40 has shown that of all accidents logged during that time, an estimated 20% were caused by drivers falling asleep at the wheel.

These accidents are difficult to pin down, as drivers were often either unaware that they had fallen asleep, or were reluctant to admit doing so for fear of legal repercussions. Professor Jim Horne, Director of Loughborough University’s Sleep Research Laboratory was behind the study. “We need to heap social opprobrium on sleepy drivers, in the same way that we currently do with drunken drivers” he notes, citing the fact that drivers are aware that they feel sleepy and, in this country at least, are under a legally binding duty of care. This is not so in the USA, where a recent study of long distance truck drivers found that an astonishing 25% admitted falling asleep at the wheel in the last year. The actual figures will be far higher.

There is a definite pattern to Sleep Related Vehicle Accidents (SRVAs). They occur mostly between two and six in the morning, with another peak between two and four in the afternoon. The early morning victims are usually young men, the early afternoon culprits older men. The accidents are frequently horrific due to the sleeping driver’s non-application of the brakes.

But why men? “Young men especially have a genuine feeling of invulnerability” reckons Horne, noting that many would be willing to undertake a long, late night journey due to social or peer pressures. Many young men filmed on the university’s driving simulator seemed genuinely surprised when informed that they had indeed fallen asleep at the wheel.

Relaxation

Indeed, the cosseting, soporific comfort of modern cars has made it easier to relax at the wheel. “Ergonomics kill” claims Horne. “Cars have become beds on wheels. There are various gadgets and gizmos you can buy that allege to detect the onset of sleep, but nothing has as yet been proven to be of practical benefit.” Systems currently in development aim to measure the overall characteristics of the car’s behaviour rather than the driver’s to gauge whether the driver is in danger of drifting off.
Professor Horne was noncommittal on the question of whether our culture of long working hours and obsessive punctuality was in any way to blame for our high SRVA rate. “To be truthful, we don’t really know whether it is high at all. We’re just ahead of the game in measuring it.”

Indeed statistics from the British Allergy Foundation “Drive Against Drowsiness” campaign have pointed at another factor that contributes to the depressing SRVA statistics. Users of antihistamine drugs to counter hay fever account for 2% of all fatal accidents, and the campaign cites cases where antihistamine users have caused accidents through falling asleep at the wheel. Surrey University’s Dr Ziba Shamsi comments, “The current generation of antihistamines is described as non-sedating, but that'’ only true if they are taken at the recommended dose. It is all too easy to exceed that dose, leading to tiredness and reduced ability.”

Negative Effects

There are other sinister aspects to sleep deprivation. Mixed with alcohol, drowsiness is a killer.

Blood alcohol concentrations can be within legal limits, but low alertness during the danger hours identified means that the legal alcohol limits for driving are frequently too high. The more one suffers from drowsiness, especially in the afternoon dip, the more potent the effect of alcohol at this time.

The Answer?

So, what can be done to combat drowsiness at the wheel? The first and most obvious is not to drive when you’re feeling sleepy. Know your limitations and learn to recognise what behaviours you display that herald sleep. Should drowsiness envelop you on the sort of monotonous road where most accidents occur, pull over at the first opportunity, have a cup or two of coffee and a fifteen-minute nap before the caffeine takes effect. Short term measures such as opening the window, turning the stereo up or taking brief exercise were found to deliver at best one or two minutes respite from sleep. “

Young people aren’t that interested in coffee,” mused Horne. “Energy drinks like Red Bull which are loaded with caffeine appeal more.” Before leaving, I couldn’t help but ask him whether he had ever dozed off behind the wheel. “Good heavens, no,” he noted, “That would be the most embarrassing thing in the world. I’d have to resign.”

Volvo have taken a lead in highlighting sleepiness as a killer. Their Safety Concept Car includes a system that recognises when the car is veering relative to road markings without the use of indicators and can sound a buzzer. Cameras, which monitor a driver’s eye, have also been experimented with although this technology is still at an early stage.

It can only be good that attention is being drawn to the subject, however one basic fundamental should always be constant. If you are tired, Don't Drive.

Published: 9th July 2008