Flying under the radar: Sleepiness and driver safety

You are unlikely to drive while intoxicated, due to the entirely unacceptable risk of a collision. But would you drive while sleep deprived? Probably. But research shows there is a similar risk with both.

Williamson showed that even moderate levels of sleep deprivation are equivalent in terms of accident risk to a blood alcohol concentration of 0.1% – over the legal limit¹. Sleep problems are so common among occupational drivers, but they often remain overlooked. In the general population, insomnia is at a prevalence of 1 in 10 adults. When you add in shift working, this number becomes much higher. There is a third sleep disorder that also needs mentioning – obstructive sleep apnea (OSA). This is a sleep disorder usually associated with snoring when the airways repeatedly closes during sleep, causing pauses in breathing and extremely fragmented and poor quality sleep. Why does this need a special mention?

Anyone can get OSA, but it is more common if you are older, male and carrying extra weight. While the occupational driving cohort is diverse, this collection of risk factors is extremely common. For men aged between 30 and 49 years old with a raised BMI, the prevalence of OSA is between 18.9 and 52.9%. This is much higher than you might think, but is based on an enormous data set called the Wisconsin Sleep Cohort².

The accident risk alone associated with poor sleep is dramatic enough – 1 in 5 road traffic accidents are associated with poor sleep³. And if you have OSA, your vehicle crash risk is 2-4 times that of a driver without the condition⁴.

But the most dramatic thing about all of this, is that sleep disorders are treatable.

OSA diagnosis has become straightforward in recent years, requiring only a single-night sleep test carried out in your own home. The gold standard treatment is CPAP (continuous positive airway pressure), which blows air at a low pressure through a mask that gently holds your airway open from the inside, so you can continue to breathe freely as you sleep.

But the problem is this: drivers are afraid to come forward for diagnosis due to fears they will lose their licence.

This fear is not well founded. For perspective, we have diagnosed thousands of drivers with OSA, and we have never stopped a driving licence. It’s extremely rare to need to do this. But the fear is far more common. What results is drivers concealing the condition and driving tired with a sky-high collision risk.

In order to drive this forwards, the issue needs to be confronted head on. When we have gone into workplaces to talk about sleepiness and driving, and talk through the process and the specific DVLA requirements – people start to understand. Workforces respond to this reassurance, and we always have drivers start to come forward.

If your organisation employs drivers, you will almost certainly have undiagnosed cases of OSA. Addressing driver concerns about OSA head on enables diagnosis and treatment. And when this happens you have happier, healthier and safer drivers.

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¹ Williamson. Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occup Environ Med. 2000 Oct

² Young T. Rationale, design and findings from the Wisconsin Sleep Cohort Study: Toward understanding the total societal burden of sleep disordered breathing. Sleep Med Clin. 2009 Mar

³ Horne JA. Sleep related vehicle accidents. BMJ, 1995

⁴ Tregear S, Obstructive sleep apnea and risk of motor vehicle crash: systematic review and meta-analysis. J Clin Sleep Med. 2009 Dec