"Cruise Missiles" A Bigger Factor In Sleep Crashes Than Tiredness
Speed Limiters and Slower Speeds the Real Culprits
The dangers of driving when over tired have been highlighted recently. Reports have suggested that a driver who has had five hours sleep is as dangerous as a drunken driver, and that nearly half of drivers surveyed admitted to driving after less than five hours sleep during the past year.
The ABD has long been concerned about the number of road accidents that involve vehicles, particularly HGV's, running into the back of stationary traffic, straying onto the hard shoulder or leaving the carriageway altogether. These accidents are all sleep related, and we believe that forcing drivers to travel at one steady speed, especially one that is slower than they would otherwise choose, turns them into what Traffic Officers call "Cruise Missiles", waiting to make a lethal strike.
"The biggest factor in these accidents is not the amount of sleep the driver had the previous night, but boredom," says the ABD's Mark McArthur-Christie. "When a driver is travelling at a steady speed which is too slow to require him to make regular decisions and control inputs, he is lulled by the monotony of the passing scenery and the steady drone of his engine into a kind of stupor, which makes him vulnerable to missing obvious hazards or lapsing into full sleep."
HGV drivers have been afflicted for the past ten years with speed limiters set at 56mph - below the HGV motorway speed limit of 60mph. This means that an HGV driver will inevitably drive on the limiter rather than looking at the road and making decisions. HGV and PSV related fatalities make up 50.4% of all motorway deaths in 2002, and deaths of HGV drivers increased by 24% the year after limiters were made compulsory (1995 vs 1994)
Increasingly, speed limits are being lowered and more rigidly enforced, leading to more car drivers opting out of driving intelligently on major roads and turning themselves into cruise missiles. This is why the death rate on the Nevada freeway, in the days when it was limited to 55mph, was three times higher than the largely unrestricted German autobahns.
"The possibility of introducing satellite controlled limiters onto cars fills us with horror," continued McArthur-Christie. "We are absolutely convinced these devices would greatly increase the motorway accident rate by turning all motorists into sleepy cruise missiles."
The ABD fully agrees with the advice given to drivers who start to feel uncontrollably sleepy - stop, rest, snooze and drink coffee. We are pleased to see organisations like BRAKE backing our calls for more rest areas. However, we call on the DfT to consider more carefully the effects of their obsession with speed reduction on driver behaviour. We believe that motorway safety could be greatly improved by raising the limit to 80mph - the speed at which most drivers WANT to travel - and by setting HGV limiters at 65mph rather than 56mph, allowing drivers to control their speeds within their 60mph limit rather than being passengers in their own vehicles as they are at the moment.
The ABD condemns the idea that 5 hours sleep the previous night is some sort of magic number that triggers dangerous tiredness. Some people simply do not need that much sleep, whereas others cannot function at all with less than eight. Many are more tired at the end of a long days work than after a sleepless night. Dangerous fatigue can creep up on busy, generally tired people at any time - there is no simplistic rule - and suggesting there is one simply diverts attention away from the real problem of "cruise missiles", and from educating drivers as to how to recognise the symptoms of dangerous tiredness.
"This is typical of the road safety industry today," continued Mark McArthur-Christie. "Everything has to be reduced to a magic number. Four hours 59 minutes sleep - dangerous. Five hours one minute -safe! Next minute they will be sending policeman round to check we are all tucked up in bed. Thinking like this discredits speed limits, much reducing their usefulness as road safety tools. Repeating the same mistake over tiredness will have similarly lethal effects."