According to some studies, drivers who are tired have a 13-fold higher chance of being in a car accident than drivers who are rested. A British study linked about half of all car accidents to sleepy drivers while a US study found that over 50% of polled adults reported driving sleepy while another 20% reported falling asleep at the wheel.

The problem with driving sleepy, most researchers agree, is that our response times are much slower when we are chronically tired. In fact, response times for sleepy drivers and drunk drivers are much the same. Alistair MacLean of Queen’s University conducted a study comparing tired female drivers and rested female drivers. He had drivers get behind the wheel at 2:30 in the morning after a full day. The drivers had similar response times to someone with a 0.05 blood alcohol level. That blood alcohol level is comparable to a 160-pound man drinking three gin and tonics within an hour. By 5 in the morning with no sleep, the driver’s performance deteriorated further and was comparable to someone with a blood-alcohol concentration of 0.08 per cent.

The US estimates that the costs of car accidents caused by tired drivers amounts to $12.5 billion a year. These drivers can be in car accidents that lead to fatalities, broken bones, burn injuries, spinal cord injuries and other serious harm. Part of the problem is that when the body is very tired, an individual falls into what researchers call “micro” sleep, very tiny periods when the body rests or sleeps. Although these may only last a few seconds, that is enough time to cause a serious car accident. In addition, tired persons may simply fall asleep at the wheel.

There are many reasons why people are driving tired:

1) Occasional insomnia. Everyone suffers from occasional sleeplessness caused by changes in diet, stress levels, exercise or some other factors. If you have not been sleeping well and feel tired, though, find someone who will drive you to your destination or take a taxi.

2) Truck drivers needing to fill their quotas. Some companies pressure their drivers to drive late at night or travel long distances in order to meet work quotas. This tends to create dangerous patterns of exhaustion that can lead to accidents.

3) Sleep apnea. Sleep apnea is a medical condition that causes breathing problems during sleep. A person with sleep apnea experiences very fractured sleep and therefore suffers from exhaustion. Someone with this condition should not drive until the condition is well under medical supervision and control.

4) Medication. Some medications cause drowsiness and should not be used while driving. Also, some people who are tired try to self-medicate with caffeine pills or other over-the-counter solutions to keep themselves awake. This can be dangerous, since when the effect of the pills wears off, the driver may well fall asleep.