Rainy Day Refresher

It’s perhaps surprising, but true: Driving on a rainy day is more dangerous than driving on a snowy one. When the rain starts to fall and pavement is wet, your likelihood of a crash is higher than during wintry conditions like snow, sleet and ice, according to data from the National Highway Traffic Safety Administration (NHTSA).

After averaging 10 years of statistics, NHTSA researchers found that 46 percent of weather-related crashes happened during rainfall, but just 17 percent while it was snowing or sleeting. Those statistics are partially explained, of course, by the fact that many drivers have the good sense to stay home during a bad snowstorm, says Debbie Hersman, president and CEO of the National Safety Council, which offers defensive driving courses. But the statistics also reflect a sobering truth, she says: Drivers often do not respect the rain, and fail to adjust their driving habits to hazardous conditions.

Here is how to reduce the chances of being a rainy day statistic, according to safety experts.

Get Your Car Rain-Ready: Tire tread is key, says Bill Van Tassel, Ph.D., manager of driver training programs for the AAA national office in Orlando, Florida. Dig out a quarter (forget the old advice about Lincoln’s head on a penny, as some researchers have found the quarter test more accurate). Insert it upside down into your tire tread. “If part of Washington’s head is always covered by the tread, your tires have more than 4/32 of an inch of tread remaining. If the top of Washington’s head is exposed at any point, you should replace the tires.”

According to NHTSA, tires with 2/32 of an inch of tread are unsafe. However, you may want to replace tires before they get this worn, depending on driving conditions.

• Tire pressure is important, too, he says. You should check the pressure once a month, using a tire gauge. NHTSA offers many other tire safety facts.
• Check your windshield wipers to be sure they’re up to the task. If they need replacing and you’re doing it yourself, you can check online guides to be sure you’re doing it correctly.
• Check headlights, taillights, brake lights and turn signals to be sure all are working properly. When you’re driving, turn on your headlights to boost your visibility. Some states require the use of headlights when windshield wipers are in use.

Slow down: Driving too fast for conditions is especially dangerous on wet pavement because your tires lose traction with the precipitation, Van Tassel says. “When roadways are wet, the friction is reduced between the tire and the road,” Hersman adds. No friction is a bad thing. Tires are meant to grip the roads, not slide on them.

How much does traction decline in wet weather? “You might lose about one-third of your traction,” Van Tassel says. And that figure is why this recommendation makes sense: Reduce your speed by about a third when it’s wet or rainy. If the speed limit is 55 mph, aim for under 40 mph. “That is not a hard statistic but a rule of thumb,” he says.