How Hydroplaning Works

How Hydroplaning Occurs

A London taxi cab drives through a patch of standing water, risking hydroplaning, after a heavy downpour.
A London taxi cab drives through a patch of standing water, risking hydroplaning, after a heavy downpour.
Michael Bradley/Getty Images

To understand how hydroplaning works, you need to know how traction works. Traction is the friction that builds up between the tires on a car and the pavement. Rolling traction is the interaction between the tire and the surface, which results in forward motion. When water coats that surface, the tire can't obtain traction. Hydroplaning occurs when your tires move over a wet surface so quickly that they don't have time to displace enough water and contact the surface. The water lifts the tire up from the surface, and the vehicle begins to hydroplane.

While speed, road conditions and tire wear all play a part, the main cause of hydroplaning is water depth. Hydroplaning is possible whenever water accumulates to a depth of one-tenth of an inch (0.3 centimeters) or more for at least 30 feet (9.14 meters) and a vehicle moves through it at 50 miles per hour (22.35 meters per hour) or more [source: Crash Forensics]. Tire size and tread patterns are also important. Hydroplaning is more likely to happen if your vehicle has narrow tires. Worn tires are more dangerous in wet conditions. Certain tire tread patterns are better at channeling water away than others. All-wheel drive vehicles are more likely to hydroplane than two-wheel drive vehicles, because their computerized differentials may shift power from the front to the rear tires, creating a hydroplaning situation. Heavy vehicles are less prone to hydroplaning.

Regardless of your tires or what type of vehicle you drive, there are a couple of things you can do to prevent hydroplaning. First, slow down. Speed increases the likelihood of hydroplaning. Even if you do hydroplane, going slower will mean you're in less danger. Another tip: Watch the drivers ahead of you. Erratic steering from them could mean you're coming to a dangerous patch. If the cars ahead of you suddenly throw up more water, it may mean that they've run through a puddle that could cause you to hydroplane.

Now, let's figure out what to do if (and when) you find yourself in a hydroplaning situation.