What is hydroplaning?

Alantabuck

I am new to driving, many people say in the rainy season to be careful with hydroplaning, but it is not clear and if so, how should I avoid it?

Xaquin

not entirely sure if this is a serious post, but it's what happens when your car is moving fast enough that the tires cannot displace the water beneath them causing the car to lose traction and possibly crash (depending on your speed, the depth of the water, whether you're turning, and a lot of other factors).

edit: avoid it by driving around the speed limit during rain and slightly slower during sleet/snow. don't drive through running water of unknown depth.

Blarghy

Hydroplaning is basically your car losing traction on water and sliding, slipping, or spinning out as a result. The standard defensive driving tools apply to it. Slow down. Avoid sharp turns. Leave plenty of space between your car and the car in front of you.

Ark Evensong

State of your tires can have a significant impact, too. Make sure they're not too worn and at the right pressure.

Wikipedia has a decent article on it as well. https://en.wikipedia.org/wiki/Aquaplaning
Some of the relevant parts:

Response
What the driver experiences when a vehicle aquaplanes depends on which wheels have lost traction and the direction of travel.

If the vehicle is traveling straight, it may begin to feel slightly loose. If there was a high level of road feel in normal conditions, it may suddenly diminish. Small correctional control inputs have no effect.

If the drive wheels aquaplane, there may be a sudden audible rise in engine RPM and indicated speed as they begin to spin. In a broad highway turn, if the front wheels lose traction, the car will suddenly drift towards the outside of the bend. If the rear wheels lose traction, the back of the car will slew out sideways into a skid. If all four wheels aquaplane at once, the car will slide in a straight line, again towards the outside of the bend if in a turn. When any or all of the wheels regain traction, there may be a sudden jerk in whatever direction that wheel is pointed.

Recovery
Control inputs tend to be counterproductive while aquaplaning. If the car is not in a turn, easing off the accelerator may slow it enough to regain traction. Steering inputs may put the car into a skid from which recovery would be difficult or impossible. If braking is unavoidable, the driver should do so smoothly and be prepared for instability.

If the rear wheels aquaplane and cause oversteer, the driver should steer in the direction of the skid until the rear tires regain traction, and then rapidly steer in the other direction to straighten the car.

Prevention by the driver
The best strategy is to avoid contributors to aquaplaning. Proper tire pressure, narrow and unworn tires, and reduced speeds from those judged suitably moderate in the dry will mitigate the risk of aquaplaning, as will avoidance of standing water.

Electronic stability control systems cannot replace defensive driving techniques and proper tire selection. These systems rely on selective wheel braking, which depends in turn on road contact. While stability control may help recovery from a skid when a vehicle slows enough to regain traction, it cannot prevent aquaplaning.

Because pooled water and changes in road conditions can require a smooth and timely reduction in speed, cruise control should not be used on wet or icy roads.

mRahmani

Pretty much everybody here has covered it. Fall 2008 I had a Camaro with worn tires, hydroplaned, and went spinning across 3 lanes of highway traffic before going face first into a bridge support.

To avoid it:

Reduce speed on wet pavement, especially when it has just started to rain. The beginning of a rain storm will lift up oil that has dripped onto the road and make it extra slick.

Check your tires periodically. They should have sufficient tread and be at the correct pressure.

Avoid cruise control in the rain, especially in older cars. While cars newer than 2010 or so have traction and stability control, older cars didn’t and won’t recognize that a tire is slipping, and will continue to apply throttle.

Kruite

Also realize that rain is not necessary for your car to behave this way.

Oil slick, wet leaves, sleet/hail slurry, snow, mud, can all cause your tires to lose traction with the road/ground.

Tastyfish

Blarghy wrote: »

Hydroplaning is basically your car losing traction on water and sliding, slipping, or spinning out as a result. The standard defensive driving tools apply to it. Slow down. Avoid sharp turns. Leave plenty of space between your car and the car in front of you.

It's very much important to point out that you can't break whilst hydroplaning/aquaplaning. The danger is that your wheels aren't actually in contact with the road.
You're moving along a plane of water that is on top of the water in direct contact of the road.

Go slow when there is a risk, don't try to go slower when it starts.

BlindZenDriver

Just want to add that the width of tires and the weight of the vehicle makes a difference, like for example a light sports car with wide tires will aquaplane way earlier than something heavy - that is even more so if the car is on tires that have a minimum of thread.

Unknown

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V1m

https://www.youtube.com/watch?v=TdwuftIUwYY

BlindZenDriver

Orca wrote: »

To reiterate what Ark posted: when you notice hydroplaning, freeze your inputs. Foot off the gas, try to limit steering inputs to just keep you straight. Don't hit the brakes, don't hit the accelerator, definitely don't jerk the wheel.

I would add that foot of the gas doesn't mean removing the foot like you're were about to emergency brake, instead be a little gantle as depending on the car you will otherwise find engine braking as an undesired result.

Unknown

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spool32

Hey, this brings up an actual corollary question: how do you manage the braking while driving a Tesla? They apply gentle brake when you lift off the gas, as part of the regenerative system.

mRahmani

spool32 wrote: »

Hey, this brings up an actual corollary question: how do you manage the braking while driving a Tesla? They apply gentle brake when you lift off the gas, as part of the regenerative system.

Good question! I should check in with the Tesla guys at work to be sure, but the general idea is this:

All cars since 2012 have federally mandated stability control systems. Among other things, the system monitors wheel speeds and lateral acceleration. If the wheel speeds drop faster than a certain rate, wheel slip is detected and regen braking will be disabled until the condition is gone. This is at least how the system functions on ice and snow, but the general principle when hydroplaning should be similar - the tires lose contact with the ground and lose traction. So if you’re hydroplaning, there may be a brief decel attempt (<1s) before the car gives up and coasts.

There’s likely additional parameters that are looked at, such as expected vs actual deceleration according to G sensors. I haven’t worked on the ABS side of things too much, just traction and stability.