What to Do If You Hydroplane: Rain Driving Without Panic

It usually starts with a strange lightness. The steering wheel suddenly feels loose, the engine note rises a little, and the car seems to float. That's hydroplaning: your tires have stopped touching the road and are riding on a film of water. It lasts only a moment, and how you respond in that moment decides whether it's a scare or a crash. Here's what to do if you hydroplane, why it happens, and the habits that keep it from happening at all.

What hydroplaning is

Tire treads are designed to channel water out from under the tire so the rubber can grip the pavement. When water builds up faster than the treads can clear it, a wedge of water forms in front of the tire and lifts it off the surface. With nothing gripping the road, steering and braking stop working normally.

Three things make that more likely:

• Speed. The faster you go, the less time your tires have to push water aside.
• Tread depth. Worn tires have shallow grooves that can't move much water.
• Water depth. Puddles, ruts filled with water and standing water at low spots are the danger zones.

Light vehicles, underinflated tires and wide tires can all add to the risk. You can't change the rain, but you can control your speed and your tires.

What to do if you hydroplane: 5 steps

1. Ease off the gas. Lift your foot from the accelerator gently. Slowing down lets the tires work back through the water to the pavement.
2. Don't slam the brakes. Hard braking while hydroplaning can lock the wheels or send the car into a skid once the tires grip again. If you must brake, press gently. With anti-lock brakes (ABS), firm steady pressure is fine; don't pump.
3. Hold the wheel steady and look where you want to go. Keep steering straight, in the direction you want to travel. Avoid sudden turns. Your hands tend to follow your eyes, so look at your lane, not at the ditch.
4. If the rear slides, steer gently in the direction you want the front to go. Make small corrections. Big jerks of the wheel cause the car to swing the other way when traction returns.
5. Wait for the grip to come back, then recover slowly. You'll feel the steering firm up. Straighten out, settle your speed lower than before, and if you're shaken, pull off somewhere safe and take a breath.

Most hydroplaning episodes last a second or two. Drivers get into trouble when they overreact: stomping the brake, yanking the wheel. Calm, small inputs are the whole technique.

Why speed and tread matter

Speed is the factor you control from moment to moment. Slowing down on wet roads is the single best way to prevent hydroplaning. The Insurance Institute for Highway Safety's research on speed explains how higher speeds increase both the risk of losing control and the severity of crashes, and wet roads magnify that.

Tread is the factor you control before you leave the driveway. NHTSA recommends replacing tires when tread wears down to 2/32 of an inch, and tires have built-in wear bars at that depth. You can check with the penny test: put a penny into the tread upside down. If you can see the top of Lincoln's head, the tread is too shallow. Wet-weather grip declines steadily as tires wear, so many drivers replace tires before they reach the legal minimum.

Also check pressure monthly. An underinflated tire squashes the tread grooves together and can't clear water as well.

NHTSA's winter driving tips include a similar maintenance list, and most of it applies to rainy seasons too.

The first part of a rainstorm: the slickest roads

Roads are often at their most slippery when rain first begins, especially after a dry spell. Oil, rubber and grime build up on the pavement, and the first rain lifts them into a slick film before heavier rain washes them away.

That means the start of a storm calls for extra care even when the rain looks light. Slow down early, avoid sudden moves, and give yourself more time for everything.

Following distance in the rain

On wet pavement it takes longer to stop, and you're more likely to need to stop suddenly as other drivers misjudge conditions. Double your normal gap, at minimum. If you use the method in our guide to the 3 second rule, that means counting to six or more behind the car ahead.

Other wet-road habits:

• Drive in the tracks of the car ahead, where tires have pushed some water away (but at a safe distance).
• Avoid the outside lanes when water pools there, and steer around puddles when you can do it safely.
• Never drive through flooded roads. You can't see the depth or whether the road beneath is gone.
• Turn on your low-beam headlights. In poor visibility, our guide on when to use high beams explains why low beams are the right choice.

Driving slower than the posted limit in heavy rain isn't just smart; in many situations it's the law, because you're required to drive at a speed that's safe for conditions. Read about the basic speed law for the details.

Skids that aren't hydroplaning

Not every slide is hydroplaning. You can also skid on wet leaves, ice or gravel, or by braking or turning too hard. The recovery is similar:

• Braking skid: Release the brake enough for the wheels to roll, then brake gently. With ABS, keep firm pressure and steer.
• Rear-wheel skid: Ease off the gas and steer gently where you want the front of the car to go.
• Front-wheel skid (car keeps going straight when you turn): Ease off the gas and slightly unwind the steering so the tires can regain grip, then steer again.

Permit tests often ask which of these to do, and the answer is almost always: ease off, don't overreact, steer where you want to go.

Practice and preparation

You can't safely practice hydroplaning on public roads, but you can practice the habits: slowing early when rain begins, keeping cruise off, scanning for standing water and keeping your hands relaxed on the wheel. Talk through what to do if you hydroplane with your supervising driver before the next rainy drive. Then quiz yourself on the wet-weather questions with our free practice tests.

Frequently asked questions

Should you brake when hydroplaning?

Avoid hard braking. Ease off the gas and hold the wheel steady; if you need to brake, press gently, or use firm steady pressure if your car has ABS.

At what speed do cars hydroplane?

There's no single speed, because it depends on water depth, tire tread, tire pressure and the vehicle. The risk rises as speed increases, which is why slowing down is the best prevention.

Why are roads slippery when it first rains?

Oil, rubber and dirt build up on the road during dry weather. The first rain mixes with them to form a slick film until heavier rain washes it away.