Rain and hydroplaning — Arizona Permit Test

Be extra careful during the first 30 minutes after rain begins, when grime and oil mix with water and make the road slippery.

The first rain lifts oil off the road into a slick film. Later rain washes it away, so the start of a storm is the worst.

Be extra careful during the 30 minutes after rain begins; grime and oil on the road surface mix with water and make the road slippery.

In heavy rain your tires can ride on a film of water, and at 50 mph they can lose all contact with the road.

With no grip on the road, the steering and brakes stop working. It can happen at an ordinary highway speed.

In a heavy rain, your tires can ride on a film of water, and at 50 mph your tires can lose all contact with the road.

Under-inflated, worn or bald tires lose contact with the road at much lower speeds.

Worn tread cannot push water out of the way, so a car with bad tires can start to slide at speeds that feel safe.

Under-inflated, worn, or bald tires lose contact with the road at much lower speeds.

The best way to prevent hydroplaning is to slow down.

At lower speed the tires have time to push water aside and keep touching the road.

The best way to prevent hydroplaning is to slow down.

If your car hydroplanes, hold the wheel firmly until your tires grip the road again, and do not brake.

Braking or jerking the wheel while the tires float can send the car into a spin when they suddenly grip again.

Hold the wheel firmly until your tires grip the road again.

For how long after rain begins does the manual say to be extra careful?

30 minutes. The first rain lifts oil off the road into a slick film. Later rain washes it away, so the start of a storm is the worst. Arizona Driver License Manual and Customer Service Guide, p.55: “Be extra careful during the 30 minutes after rain begins; grime and oil on the road surface mix with water and make the road slippery.”