Holding Steady on Wet Roads

Nothing cleans the roadways like a rain shower. It also extracts grime and puts a thin film of moisture between your car and the road—a dangerous combination that can send your car into uncontrollable slide.

"The most slippery conditions occur just after an extended period of dry weather when the roadway gets coated with oily water," said Mark Cox, director of the Bridgestone Driving School of Steamboat Springs, Colo. The school trains professional and everyday drivers to handle inclement weather.

What can a driver do keep their vehicle steady on wet roads?

Driving experts use the term "traction limit" to describe how fast a vehicle can before losing its grip on the roadway. Not all vehicles are the same, and road conditions dramatically affect the limit. Rain, snow, turning speed and vehicle weight all play a role in traction.

"You may be driving at the posted speed but beyond the traction limit for the conditions," Cox said.

Professional drivers adjust technique to compensate for "hydroplaning," or gliding along the surface of a wet road. And the effects of hydroplaning become worse the faster you go. Water builds up in the front of tires faster than it can be channeled off, Cox said.

Also, oil accumulates anywhere vehicles stop or park. The one-two punch of oil and hydroplaning affect dramatically reduce traction limit for all vehicles—especially at intersections.

"You should always approach intersections with caution anytime the roadway is wet," Cox said. "The posted speed limit may be too fast and unsafe for rainy roads."

Every year the driving school puts professional and amateur drivers through a variety of courses to test driving skills. Here's their list of suggestions for driving in wet weather:

• Adjust your speed to the "grip conditions." That is, slow down at oily intersections and around curves.
• Check tire condition. Tires with little or no tread can cause your vehicle to slide rather than stop. The lack of tread prevents tires from effectively channeling off water.
• Keeping extra distance between you and the vehicle in front of you. Drivers are particularly unpredictable during bad weather and you may need to suddenly stop.
• Drive within limits of vision especially at night. Creatures such as deer often jump out from the side of the road, and slick roads make it hard to take evasive maneuvers. A rule of thumb: You should be able to stop between the front bumper and edge of what you see.
• Use a light touch on the brakes and steering wheel. Sudden braking can send your car into a slide. Gently applying brakes helps your vehicle slow down safely. Brake in a straight line.
• Accelerate slowly or your tires may spin rather than grip the road.
• Avoid oversteering. Severe turns or avoidance tactics can make the vehicle spin or slide sideways. Gradual turns use the weight of the car to keep your vehicle on the road.
• Stay out of "road ruts"—the worn tracks made by trucks and heavy vehicle—when it rains. Water accumulates there and can cause hydroplaning.
• If your car does hydroplane, Cox suggested that you hold the steering wheel firmly but not tightly. Slowly let off the accelerator and allow the vehicle to come to a gradual stop. Sudden reactions or panic driving can make matters worse.

"Driving on a wet road can be as dangerous as driving on a snowy one, even more so," Cox said. "People tend to slow down when it snows but not when it rains. They usually don't realize traction is quite a bit less than a dry road."