If you're yawning, it's time to pull over!

Launching its latest road safety campaign, which is mainly being targeted at people who drive for work, the DfT said that one in five crashes was caused by tired drivers. However, people often insisted on carrying on with their journeys, despite receiving natural warning signals.

It said a recent YouGov poll had revealed that three quarters of motorists opened a window to keep themselves awake on long journeys. A few resorted to more unusual methods, such as shaking their heads vigorously (4%) and even slapping themselves in the face (3%).

More than a quarter (26%) of the 1,500 people questioned had driven for four or more hours without a break, and 4% for more than seven hours without a break, the study found. It also showed that only 18% of motorists always took a yawn as a sign to pull over.

Road Safety Minister Jim Fitzpatrick said: "We all want to finish our journeys as quickly as possible but being tired at the wheel is a proven killer that we cannot ignore.

"People who drive for work are particularly at risk but there are simple steps we can all take to make our journeys safer. Plan regular stops into a long trip and if you find yourself yawning, pull over and take a break - this could make the difference between life and death."

Driver fatigue

Dr Neil Stanley, a sleep expert from the Clinical Trials and Research Unit at the Norfolk and Norwich University Hospital, commented: "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."

The YouGov survey also showed that just one in five (22%) of drivers always planned for breaks in their journeys, while more than half (54%) at least occasionally tried to "beat their journey time" on a trip they had done before.

The Government's THINK! road safety campaign, offers the following advice concerning driver fatigue:

• Don't start a long trip if you're already tired.

• Plan your journey to include a 15-minute break every two hours.

• If you feel drowsy find a safe place to stop (not the hard shoulder).

• As an emergency measure, drink two cups of coffee or a high-caffeine drink and have a rest for 10-15 minutes to allow time for the caffeine to kick in.