A 3-minute lesson from the Delaware course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
The faster you go, the more distance you need to turn, slow or stop. Your tires are your only contact with the road, so wet, snowy, icy or loose surfaces demand lower speeds—and keeping pace with traffic matters too.
Know the rule
Stopping from 60 mph doesn't take twice the distance needed at 30 mph—it takes over three times as much.
Tires riding up on water like water skis. Most tires grip up to about 35 mph on wet roads; in heavy rain they can lose all traction at about 50 mph—lower with worn tires.
Keep pace with traffic. Going faster means constant passing; going much slower bunches traffic—pull over when safe and let vehicles pass. Speeding saves no more than a few minutes an hour.
Merge at the speed of traffic: use the entrance ramp to build speed, and don't stop at the end of it. If you must wait for space, slow on the ramp so you have room to accelerate.
A downpour starts on Route 1. Cut your speed by about 10 mph and watch for standing water. If the steering suddenly feels light, ease off the gas, hold the wheel straight and wait for the tires to grip again.
Check your understanding
Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
In a heavy rain, hydroplaning (tires riding on water) can cause complete loss of traction at speeds around
50 mph
20 mph
35 mph
70 mph
Answer: 50 mph
In heavy rain, tires can lose all traction with the road at about 50 mph, a phenomenon called hydroplaning.