Watching folks slip and slide during a recent rain prompted me to write this reminder about hydroplaning. Hydroplaning occurs when water gets in front of your tires faster than the weight of your vehicle can push it out of the way. The water pressure can actually raise your vehicle so that it slides on a thin layer of water. When this occurs, in less than a second you lose contact with the road and effectively become a water-skier!
The three main factors that contribute to hydroplaning are:
- Vehicle speed - as speed increases, wet traction is reduced
- Tire tread depth - worn tires have less ability to resist hydroplaning
- Water depth - The deeper the water, the quicker you lose traction, but thin layers of water cause hydroplaning, too
What it boils down to is that when your tires are moving over a wet surface too quickly there is insufficient time to channel the moisture away from the center of the tire. As mentioned, the water lifts the tire and you lose traction. The point at which your vehicle becomes waterborne is called the transition point. The transition point is determined by the following variables:
- Tire size - the wider the contact area relative to length, the higher the speed needed for hydroplaning.
- Tread pattern
- Tire pressure
- Water depth
- Water composition - oil, temperature, dirt, and salts change the water
- Vehicle drive-train - all wheel drive vehicles may be more likely to hydroplane in some circumstances.
- Vehicle speed - always slow down when it’s wet. Hydroplaning can occur at any speed under the right combination of conditions, but some sources define higher speeds as over 40 mph.
- Vehicle weight - the lighter the vehicle the greater the tendency to hydroplane.
- Road surface type - non-grooved asphalt is more hydroplane prone than ribbed or grooved concrete
It’s sometimes hard to tell when you’re hydroplaning. The vehicle’s rear end may be a little squirrelly. Steering may feel loose or too easy. Watch for standing water or spray from vehicles in front of you. Slow down. If you start to hydroplane, don’t apply your brakes or turn your steering wheel. Hold the wheel firmly, go straight, ease your foot off the gas until the car slows and your steering normalizes. If required to brake, do so gently with light pumping actions. For cars with anti-lock brakes, brake normally.
Are your tires checked daily for wear, tread depth, and pressure? Do the people checking them know what they’re doing? Have they been trained the same way? Do they use the same equipment? Does anybody monitor the quality of their checks? Are appropriate records maintained? These things might sound basic, but they are important because you might be betting your life on them.