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What plans for a blood test to detect tired drivers could mean in practice for motorists and the courts

Tiredness can often be cited as a factor leading to road traffic accidents with statistics saying that around a fifth of road traffic accidents are caused due to driver tiredness.

It's reported that government statistics show that in 2021, 467 people were either killed or seriously injured in collisions where fatigue was noted as a contributory factor.

Tiredness is however subjective and there’s presently no assessment of whether a driver might be so tired as to affect their ability to drive. Therefore, it’s interesting to read new developments looking at how this may be tested in the future.

Tiredness and driving research under way

Research funded by the Office of Road Safety in Australia has found, based upon the results of 61 laboratory field studies, that between four and five hours of sleep is where it may be legally possible to state that an individual is impaired owing to fatigue.

Further research has been carried out in Australia to then look at how you would be able to identify when somebody’s concentration has been impaired owing to fatigue.

Plans to develop tiredness blood test within two years

Professor Claire Anderson at Monash University in Melbourne, Australia, is leading efforts to develop a blood-based test. This test, we understand, identifies five biomarkers in bloods that can detect whether someone has been awake for 24 hours or more with a greater than 99% accuracy. Work is still ongoing to validate the markers and investigate whether they can quantify whether somebody has slept for say five hours or just two.

However, professor Anderson is said to believe that a forensic blood test for sleep deprivation could be developed in potentially the next two years and launched within five years.

But would it work in practice?

Potential complications 

While it currently seems unlikely that criminal charges could be made against a tired driver, the development of this blood test could change this.

Presently a court will consider to what extent a driver's negligence caused an accident, which includes an assessment of the reasonableness of a drivers conduct. This could involve considerations as to whether the driver was fit to drive, but it would be exceptionally hard to prove unless it involved alcohol or drugs.

But could drivers really be taken to court for being too tired?

That possibility raises many questions; for example would a change in the law to prosecute overly tired drivers be discriminatory as it would disproportionality prejudice new mums?

How accurate and fair would a test be when everybody needs different levels of sleep? It appears this could introduce an element of subjectivity for a court to try to assess whether somebody was too tired to drive.

It would also result in an offence being committed despite a lack of intent; as after all nobody wants to be over tired.


Through our work representing clients we see how traumatic road collisions are and how our clients’ lives have changed through no fault of their own. They require specialist legal advice to either access the specialist rehabilitation and therapies they require to try and regain as much of their independence as possible or to access support they need to come to terms with their loss.

At present, very much the ability to be able to drive when you are tired is left to individuals as to whether they feel safe enough to do so.

Should it be that that responsibility is removed from the individual to an external testing system, such as those in relation to alcohol and drugs, bearing in mind the consequences that the effects of driving tired can have on others on the road? Or does this go too far?

We welcome any positive steps to improve road safety and while there’s still work to be done to develop an objective test for tiredness this is certainly an interesting topic to consider, and an area to watch with interest.

Find out more about Irwin Mitchell's expertise in supporting people and families following road collisions at our dedicated road traffic accidents claims section.

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, making it easier to legislate against drowsy drivers or their employers.”