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Tuesday, November 03, 2009

How the Time Change Can Affect Your Driving

Its that time of the year again. Time to fall back and set the clocks to Standard time. The change can cause disruptions while our mind and body adapt to the new time and that disruption can extend to our driving.

Changing back from Daylight Savings Time to Standard Time occurs on the first Sunday in November and that falls on November 1st this year. The time change officially happens at 2:00 AM on Sunday November 1st. Falling back means setting the clock back one hour; at 2:00 AM set your clocks back to 1:00 AM. The great thing about falling back is that we all get an extra hour of sleep on Saturday night. Those who don't get the word will probably arrive at church an hour early and wonder where everyone is or why that football game hasn't started yet.

The time change is always somewhat confusing because it takes our minds a few days to adapt to the new change. Those of you who are used to waking up and beginning your morning commute in the dark will be waking up to the sunrise. Those who enjoy the extra sunlight after work will be getting home in the dark.

The time change in the fall isn't as disruptive as the spring time change. In spring we lose an hour of sleep and sleep experts say that losing even one hour of sleep can have an impact on our driving; driving while drowsy is just as dangerous as driving under the influence. However, even though we aren't going to lose any sleep, our driving can still be affected because of the time it takes our internal clock to adjust to the change.

Our internal biological clock or circadian rhythm, regulates our wake sleep cycle. It was easy before clocks were invented; we woke up at dawn and we went to sleep when it got dark. Sleep experts also say it is natural for us to become sleepy in the late afternoon. In the modern world, our days are regulated by the clock and that mechanical clock can sometimes come into conflict with our biological clock. Some sleep experts suggest that we follow the example of Meditteranean cultures and allow employees to nap in the afternoon in order to gain maximum performance. When we force ourselves to remain awake through that natural afternoon drowsy time, it can lead to drowsiness behind the wheel on the long commute home. One survey of drivers found that more than one-third (35%) of drivers who nodded off while driving within the previous six months say their last experience occurred between 6:00 a.m. and 5:00 p.m. An additional 17% report they nodded off between 5:00 p.m. and 9:00 p.m.

A newly released study using mice (that also has implications for humans) found that when circadian rhythm cycles were disrupted, the mice didn't perform as well in maze tests as the control group whose circadian patterns weren't disrupted. They also exhibited impulsive behavior which, for human drivers, can mean trying to beat that light or pulling out in front of another car. When darkness suddenly falls an hour earlier, drivers may find themselves driving a little faster; trying to get home before daylight fades.

Another problem occurs because light conditions at dusk - before total darkness - can be confusing. Shapes that show up clearly in daylight or in a car's headlights may not show up as clearly at dusk. A study conducted in 1995 found that the number of auto/pedestrian crashes increased substantially in the period following the time change back to standard time. Kids are still walking home from practice or trying to get in a little extra playing time with their neighborhood pals before total darkness. A University of California trauma center found a "62 percent increase in the number of children in auto-vs-pedestrian crashes and auto-vs.-bicycle crashes in the two weeks following the October time change. Of these victims, 90 percent had severe injuries and required surgery."

Until their body clock adjusts to the new time, drivers should be especially cautious during the first few weeks after the time change. Get plenty of sleep, don't give in to the impulse to rush home to beat the sunset, and be especially watchful for pedestrians.

Drowsy driving prevention week is Nov. 2 – 8. For more information on sleep and sleep disorders, visit the National Sleep Foundation’s web site at:

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