Speed and road conditions — South Carolina Permit Test

Always reduce speed before entering a curve, to a speed that lets you apply slight, constant acceleration through it.

Slowing in the curve itself shifts weight and grip just when the tires are working hardest.

Curves—Always reduce speed before entering a curve to a safe speed (a speed that allows you to apply slight and constant acceleration through the curve).

Hard braking after entering a curve could cause the tires to lose traction.

In a curve the tires are already using grip to turn, and hard braking can exceed what is left.

Hard braking after entry to a curve could cause the vehicle tires to lose traction.

Reduce speed at the first sign of rain, snow, sleet, or ice.

On slippery roads tires grip less, so stopping takes longer and turning can start a skid.

Reduce speed at the first sign of rain, snow, sleet, or ice.

Hydroplaning is when the steering tires ride on a layer of water on top of the road surface.

A tire riding on water has almost no grip, so steering and braking stop working.

Hydroplaning—Hydroplaning occurs when the steering tires ride on a layer of water on top of the road surface, similar to the action of water skis.

The best way to avoid hydroplaning is to slow down in rain or on a road with pooled water or puddles.

Tires shed water better at lower speed, so they stay in contact with the road.

The best way to avoid traction loss from hydroplaning is to slow down when driving in the rain or on a road that is wet with pooled water or water puddles.

When should you slow down for a curve?

Before you enter the curve. Slowing in the curve itself shifts weight and grip just when the tires are working hardest. South Carolina Driver's Manual, p.95: “Curves—Always reduce speed before entering a curve to a safe speed (a speed that allows you to apply slight and constant acceleration through the curve).”