The government has launched a high-profile campaign, fronted by actor Joseph Fiennes, to try to cut down on driver fatigue.
The slogan is ‘Don’t drive tired’.
In an effort to encourage drivers to recognise when they are not as alert as they should be, drivers are being told that as soon as they yawn, they should be seeking a safe place to pull over.
They should then either take a nap or use two high-caffeine drinks – bearing in mind that it takes 15 minutes for the body to absorb caffeine and for it to take effect.
Dr Neil Stanley, a sleep expert from the Clinical Trials and Research Unit at the Norfolk and Norwich University Hospital, said: "People read a yawn all wrong – they often mistake the energising effect that comes immediately after as a sign they can carry on, but tests prove this is not the case.
"Yawning quite simply means you’re on the road to falling asleep – so if you’re yawning behind the wheel it really is time to pull over."
Three quarters of motorists say that they attempt to drive on through fatigue by opening a window. The government say that this is not a solution.