Recently I have been driving longer and longer distances. I'm wondering if there is a safe limit to the length of time you can drive, and if you have advice on staying alert or know any gadgets that can help fight fatigue? - Joseph in Dryden, Ont.
Well, I certainly wouldn't recommend the Dudley Dave treatment - taking "little white pills" to last "six days on the road."
One thing is for sure, you're not alone. During holiday periods more of us are likely to jump in the car and undertake mammoth drives across, or up and down the country. It's tempting to get that few kilometres further, or beat your personal best to reach your destination without a stop.
According to the Canadian Council of Motor Transport Administrators, impairment by driver fatigue is a factor in approximately 15 per cent of all road collisions. At least 20 per cent of Canadians admit to nodding off at the wheel, and more than 400 die each year due to drowsy or tired driving.
"You need sufficient sleep to perform well, and driving is no exception. Most people know little about the limits of their body, and the importance of sleep and the role it plays in safe driving," says Dr. Kimberly Cote, professor in Brock University's psychology department, and director of the sleep research laboratory.
"There is no magic pill or substance which will keep you alert. Caffeine can be a temporary countermeasure to sleepiness, but having a couple of double-doubles in lieu of sleep will never work. Sleepiness is a powerful drive; it will always win over."
What's often referred to as "driver fatigue" is actually two things. One is fatigue due to long-distance driving, and the other occurs when you haven't had enough sleep. So how do you know if you have a "sleep debt," and how much sleep do you require?
"For adults it's about 7.5 hours. Some can get by on 6, others require 9, so you have to know your individual need, and make an effort to get that sleep on a regular basis. You do this simply by paying attention to how well rested you feel during the day. If you're falling asleep at inappropriate times, then you're not getting enough sleep," says Cote.
In terms of how it affects your ability to perform, sleep deficiency has been compared to impairment caused by blood alcohol levels.
"Sleepiness is like being drunk in terms of your performance level. Also, in terms of what sleepiness does to the brain, it's very similar to alcohol, it impairs your judgment," says Dr. Cote.
"There's research that shows if you stay awake for 18 hours - normally we're awake for 16 - this produces a performance impairment equal to about a 0.05 blood alcohol concentration. And if you've been awake 24 hours, your performance is equivalent to someone with a blood alcohol level of .10. Alcohol and sleepiness are very interactive; another study revealed that when you've had only four hours of sleep and just one drink, it's equivalent to having had six drinks in terms of your performance."
You can have sufficient sleep, and still experience fatigue on the road. This is usually caused by the length of time you drive without taking a break, though other causes include visual fatigue due to a dirty windshield, or reflected objects from the dash.
"Our bodies aren't meant to drive for 10 hours and maintain attention for that long; that's why you have to take breaks even if you've had enough sleep. The general rule, what the experts advise to minimize risk, is to take a break every two hours or 100 miles of driving," says Cote.
The bottom line is, if you're sleepy it's imperative that you pull over and rest.
To restore alertness, a 15-minute nap is recommended by Cote and other experts. Remember to leave enough time afterward for grogginess to dissipate; take a short walk, stretch, or pick up a coffee before getting back behind the wheel.
And what about tricks or gadgets that claim to counter fatigue? Rolling down the windows, turning up the radio, eating, or talking to the person next to you will not solve the problem.
"I would really caution against gadgets. A lot are marketed without any testing. I remember one which clipped on your ear, and when your head moved forward this would set off an alarm. The problem is, once your head bops you're actually in stage two sleep. When you've reached this stage, you're already not able to function - you're not hearing what's going on, you're not visually processing, you don't have the motor ability to operate the vehicle. That's just one example of a gadget which is quite dangerous," says Cote. "Bottom line, there is no known gadget on the market that will keep you alert."
To help ensure a safe long-distance journey, make sure you've had the sleep you need ahead of time. Avoid overnight driving, and make sure you plan your journey time to include the proper breaks to stay sharp.
E-Mail Ask Joanne at globedrive@globeandmail.com
Joanne Will