By RONALD E. HERRIOTT, U.S. Army Corps of Engineers, Louisville District, Louisville, Ky. May 31, 2012
After an uneventful drive around the city, we merged onto Interstate 10 and continued east. Our daughter had already fallen asleep in her car seat in the back. The rain began coming down harder and my wife and I got into a somewhat heated "discussion," which distracted me from my driving.
As a result, I lost track of how fast we were going. As the rain worsened, so did our argument and I picked up speed, hitting 74 mph as I topped a rise. My tires suddenly lost traction with the pavement and began riding on a thin layer of water. I was hydroplaning! What happened next probably didn't last more than 20 seconds, but it felt like an eternity.
I had no control over the vehicle as we went down the rise. Regardless what direction I turned the steering wheel, the Bronco remained in a slow spin as it went down the interstate. Time seemed to almost freeze and I was acutely aware of my thoughts and actions. I looked over at my wife and yelled, "I have no control!"
The vehicle headed toward the median and spun through the soft grass, sending mud and grass flying everywhere. I was afraid one of my tires might catch an edge on a firmly embedded rock, stick or something else protruding above ground. That was a particular concern because the Bronco's high center-of-gravity made it prone to rollover accidents. Ahead I could see a 6-foot-wide drainage culvert with a 4-foot drop-off. As we got closer, I was expecting us to hit the drop-off and flip over. Fortunately, the Bronco stopped just short of the culvert.
I looked at my wife, took a deep breath, said a quick prayer of thanks and relaxed my white-knuckle grip on the steering wheel. Even though we'd been out of control and attempting to steer didn't help, I'd still hung on for dear life. I leaned over to hug my wife and we both checked the backseat to see if our daughter was OK. Surprisingly, she was still sleeping soundly. Exiting the vehicle, I did a walk around and saw the only damage was some mud and grass on our Bronco. I then locked the hubs and drove back onto the interstate toward our destination.
When we arrived at the farm, my father-in-law, who was a former Air Force fighter pilot, told me about a hydroplaning accident he had in an F-101 jet fighter. He said he was landing at Ellington Air Force Base, Texas, on a rain-drenched runway. As he touched down, his tires began riding on a thin layer of water, making the aircraft's brakes useless as he tried to decelerate. He was still going at a pretty good clip when his tail hook failed to grab the barrier and he ran off the end of the runway. Another pilot in my father-in-law's squadron was a NASA test pilot doing research on hydroplaning. My father-in-law learned that the minimum hydroplaning speed equals nine times the square root of your tire inflation pressure in pounds per square inch.
For most automobiles, the recommended tire pressure is between 35 and 40 psi. This means when driving on wet roads, your maximum speed should be less than 54 mph. You can calculate this by using 36 psi as your tire pressure, taking its square root, which is 6, and multiplying it by 9 to come up with 54 mph.
To drive safely in wet and rainy conditions, reduce your speed to below 54 mph for your protection as well as others. Remember, it only takes a second before you're no longer in control.
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When the Roads are Wet and Wild
• Prevent skids by driving slowly and carefully, especially on curves. Use a light touch when steering and braking.
• If you do find yourself in a skid, remain calm, ease your foot off the gas and carefully steer in the direction you want the front of the car to go. You must be prepared to turn the steering wheel repeatedly until your vehicle is traveling in a straight line. For cars without anti-lock brakes, avoid using your brakes if possible. If your car has ABS, brake firmly as you steer into the skid.
• Avoid hydroplaning by keeping your tires inflated correctly. Maintain good tire tread. (Editor's note: The old standard of sticking a penny into your tread to see if it touches Lincoln's head may not be the best advice. Check out the stopping tests at http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=85 and consider using a quarter instead). Don't put off replacing worn tires. Slow down when roads are wet and stay away from puddles. Try to drive in the tire tracks left by the cars in front of you.
• If you find yourself hydroplaning, do not brake or turn suddenly as this could throw your car into a skid. Ease your foot off the gas until the car slows and you can feel the road again. If you need to brake and your vehicle doesn't have ABS, do it gently with light pumping actions. If your car has ABS, then brake normally. The car's computer will automatically pump the brakes much more effectively than a person can do.
• A defensive driver adjusts his or her speed to the wet road conditions in time to avoid having to use any of these measures.
Information reprinted with permission from the National Safety Council