How to Drive Safely in the Rain

Have you ever slid, lost control or been involved in an accident in the rain? If you have, you're not alone.

Most people are at greater risk than they realize when driving in the rain. In fact, in 39 of the 50 states, more deadly car accidents occur in rainy conditions than in snow and ice. This came to light last year after an analysis of National Highway Traffic Safety Administration data by the Auto Insurance Center.

Road conditions are most dangerous at the beginning of a heavy downpour because oil and debris pool at the surface. making roads even slicker. Knowing how to deal with poor traction reduces the potential for skidding or hydroplaning (a loss of control when tires are separated from the road by a layer of water).

One way to rainproof your driving is a course in how to properly handle a car on wet streets. Andy Van Cleef is a professional driving instructor at the BMW Performance Center in upstate South Carolina. BMW Performance Driving Schools teach adults and teens how to safely navigate these conditions while providing a better understanding of handling and vehicle characteristics in the rain. BMW has another Performance Center near Palm Springs, California.

Part of each course covers the physics of driving, which includes how much rubber is actually hitting the road at different times.

"When it's raining, essentially, you lose about 40 percent of your grip," Van Cleef says. He adds that most people don't realize that, and assume their car's stability control will manage conditions for them.But modern car technology does not absolve drivers from using common sense in poor conditions. As an example, while anti-lock brakes will control braking and pedal modulation in the rain, it cannot manage a sudden turn or overcorrection of the steering wheel. "I think the most important thing to do when it is raining is to slow down," Van Cleef says.

In dry conditions, when you double your speed, it quadruples your braking distance, he says. That is, at 1 O mph, it takes 1 O feet to brake and at 70 mph, it takes 140 feet. "But that could be more like 240 feet in the rain," adds Van Cleef. "Those numbers really make you think when you're driving 70 in the rain down the highway."

Every BMW driving course includes a wet track. Drivers learn how to use "CPR" in the event of a skid: Correct, Pause and Recover. Developing this ability in a controlled environment helps prevent panic when it happens in real life. Understanding the physical dynamics at play, and looking where you want to go instead of where you are going is crucial in steering the car to safety.

"You don't have time to think about this; it has to be a reflex," Van Cleef says. "That is why we practice this."

AAA and other auto safety organizations recommend turning off cruise control when driving in the rain. But you might want to turn on your defroster to keep the inside of your windows clear. If the glass gets foggy, open a window slightly and turn the defroster fan toa higher speed, AAA recommends. Then use your air conditioner to reduce humidity.

Make sure your car's exterior equipment is rain-ready, too. Tires, brakes, windshield wipers and headlights must be working properly.

Tires are critical when it comes to control in the rain, Van Cleef says. Check your tire depth. Experts recommend you replace your tires at 4/32-inches of tread depth or you risk hydroplaning in the rain.

"If you have worn out tires or they are hard because they are old, the contact patch where the tire and road meet is like a marble on a tile floor. It should be like an eraser on a pencil."

Unfortunately, there is no formula to predict exactly how long tires will last because there are so many factors that affect tire wear, including driving habits, weather conditions. tire type and how often you have them rotated, according to the Tire Industry Association. Every manufacturer has its own guidelines, so check with your dealer if you are unsure whether your tires need replacing.

It's easier to tell when brakes are going bad; they should be serviced at the first sign of worsening.

Windshield wiper blades should be cleaned regularly and replaced once or twice a year.

Headlights also make a difference in the rain. When you drive on wet streets, mud can splash onto your car's headlights and reduce illumination by up to 90 percent, according to AAA. So it pays to stop periodically and clean them off if you don't have a headlight washer system.

And don't forget that many states, including California, have laws that require drivers to turn on headlights in the rain and when visibility is below a certain threshold, no matter the time of day.

Originally published in the Los Angeles Times brand publishing special section Ultimate Drive on February 8, 2016.