A new blood test could introduce a law for the minimum number of hours of sleep that are needed to drive.
With around one-fifth of road accidents thought to be linked to tiredness, the test would detect whether someone is too sleep-deprived to be driving and could be available in the next five years.
Nature and Science of Sleep published a study last month, which suggested the risk of having a crash could be doubled if a driver has slept for less than four or five hours in the previous 24 hours.
While drunkenness is measured using breath and blood tests, the same does not exist for sleep deprivation. But a team claimed it has now identified five substances in the blood, including lipids produced in the gut, which can detect if someone has been awake for 24 hours.
The test was 90 per cent accurate in real-life situations, reported the researchers. However it is yet to differentiate between people who have had say, five hours or just two.
The researchers have said that, with a sleep test, new laws could eventually be written to stipulate a minimum number of hours of sleep that are needed before driving.
Leader of the team Clare Anderson, an associate professor at Monash University in Australia, 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 our capacity to manage [tiredness] is impaired because we don't have tools to be able to monitor it like we do with alcohol."
Professor Shantha Rajaratnam, also at Monash University, said: "With the right investment to be able to scale this, I reckon that within five years we will be able to implement these biomarkerbased tests at least in safety-critical industries such as trucking, commercial aviation and mining."
Professor Ashleigh Filtness, a driver fatigue expert for Road Safety GB, said: "There is already legislation stating that all drivers must be fit to drive their vehicles. Alertness is no different to any other requirement for safe driving."
The 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."
