Driving while drowsy is like driving under the influence of alcohol. Unfortunately, there is no test to determine sleepiness like there is for intoxication (Driver in fatal crash 'had not slept for at least 24 hours'; Sept 21).

A way to determine a driver's state of alertness needs to be found so that penalties for driving while drowsy, such as fines or even jail time, can be implemented. This should be supplemented with campaigns to educate the public about the dangers.

Driving while sleep-deprived is avoidable. People can simply pull over and take a nap.

But many tired drivers prefer to take the risk, thinking they can make it to their destination without incident.

Some believe simply turning on the radio or opening the car window will keep them alert, but these are unproven at best and sound more like myths.

We do not know the exact moment when sleep overcomes our bodies.

Tired drivers are less able to pay attention to the road, have a slower reaction time and have reduced ability to make good decisions.

Drivers should look out for warning signs such as frequent yawning or blinking, difficulty remembering the last few kilometres driven, missing their exit and drifting from their lane.

If drivers experience any of these signs, they should pull over to rest or change drivers, for safety's sake.

Drivers should also get enough sleep, develop good sleeping habits and avoid late-night TV or Internet surfing.

Those who have sleep disorders or are on medication that causes drowsiness should also refrain from driving.

While not all incidents may result in serious accidents, near misses are equally dangerous.

Francis Cheng