Chapter 8 · Rules
Stopping and Following
Stopping distances, the three-second rule, ice, rain, and rear-end crashes.
It takes longer than you think
Total stopping distance is reaction distance plus braking distance. At 20 mph you need roughly 60 feet. At highway speed the number climbs into the hundreds of feet. Fatigue, alcohol, phones, and speed all stretch reaction time.
- Following (city)
- One car length per 10 mph
- Following (open road)
- Three-second gap (four in bad weather)
- Motorcades
- At least 200 feet outside business/residential areas
The three-second rule
Pick a fixed point. When the vehicle ahead passes it, count “one-thousand-one, one-thousand-two, one-thousand-three.” If you reach the point before you finish, you are too close. Add a fourth second in rain, at night, behind a motorcycle or truck, or when someone is tailgating you (then also leave an out).
Rain, ice, and ABS
Roads are slickest just after rain begins — oil floats up. Slow down. Hydroplaning is tires riding on water; ease off the gas and steer straight. On ice, avoid sudden inputs. If you skid, take your foot off the brake and steer in the direction of the skid. With ABS, press firmly and steer — do not pump. Without ABS, threshold brake (maximum braking just before lockup). Never tap ABS.