A blood test to measure whether a driver who has caused an accident was impaired by lack of sleep could be available within two years and could pave the way for prosecutions, experts say.

The research, funded by the Australian Government Office of Road Safety, suggests that driving on less than five hours’ sleep is as dangerous as being over the legal drink-drive limit in many countries.

It could also provide a “line in the sand” that could enable people to be prosecuted for driving while fatigued, which many sleep experts are calling for.

“There has to be a system to check whether someone has had enough sleep, because they could be putting other people’s lives at risk,” said Prof Steven Lockley, a sleep expert at Harvard medical school, who advises Nasa on sleep safety.

There is no doubt that drowsiness kills. In Scotland, which recently launched a national campaign to raise awareness of the issue, fatigue is a contributory factor in about 50 fatal and serious injuries each year. Worldwide, between 10% and 20% of all road crashes are estimated to be fatigue-related.

In the UK, a tired driver who kills someone can be charged with death by dangerous driving or death by careless driving. Professional drivers of goods and passenger road vehicles must maintain logbooks, record hours of work and rest, and many commercial fleets use event data recorders, which police can study if a vehicle is involved in a crash. Yet proving that a crash was caused by driver fatigue is still an onerous task.

Prof Clare Anderson, at Monash University, in Melbourne, Australia, who is leading efforts to develop a blood-based test, said: “When you look at the major killers on the road, alcohol is one of them, speeding is another, and fatigue is one of them. But even though the solution to fatigue is quite simple, which is to get more sleep, our capacity to manage it is impaired because we don’t have tools to be able to monitor it like we do with alcohol.”

Many sleep experts agree that legislation is needed to reduce deaths from drowsy driving. Almost half of UK drivers have admitted to driving after less than five hours’ sleep, while experts estimate that fatigue-related crashes are likely to account for up to 20% of all UK vehicle collisions, and one quarter of fatal and serious crashes.

Anderson’s team has identified five biomarkers in blood that can detect whether somebody has been awake for 24 hours or more with greater than 99% accuracy.

Follow-up studies conducted in conditions closer to real-world situations have also indicated that these biomarkers can detect whether or not someone has slept.

“We still get close to 90% accuracy at being able to detect sleep loss, which is pretty high considering all the things that are going on in people’s lives beyond just sleep,” Anderson said.

Further work is needed to validate the markers and investigate whether they can quantify whether someone has slept for, say, five hours or just two.

Anderson believes that a forensic blood test for sleep deprivation, which could be conducted alongside existing drug and alcohol tests if somebody is taken to hospital after a vehicle crash, could be ready in as little as two years.

Dr Madeline Sprajcer, a sleep researcher at Central Queensland University in Wayville, Australia, said such tests would go a long way to solving some of the enforcement issues associated with setting a legal drowsy driving limit.

“This seems to be a barrier to a lot of the people we’ve spoken with,” she said. “You can’t have a law if you’re not able to enforce it.”

British road safety organisations welcomed the development of biomarkers to detect sleepiness.

Sonya Hurt, the chief executive of the Road Safety Trust, said: “Driver fatigue is a significant and serious issue. Government statistics show in 2021, 467 people were either killed or seriously injured in collisions where fatigue was noted as a contributory factor. Therefore, any work to reduce the impact of sleep deprivation is welcome as we strive to improve road safety and save lives.”

The UK Department for Transport said: “Drivers have a responsibility to ensure they are awake and alert on the road and should seek rest when feeling tired. The government is not considering this type of testing, but we always note new ideas to make our roads safer.”

(Source: The Guardian)