A 3-minute lesson from the Idaho course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Tailgating, driving too close to the car ahead, is a common cause of crashes. Leave enough space to stop in any situation, and know how quickly your brakes stop you. Test them often, especially when the road is wet, icy, or snowy.
Three-second rule
The minimum recommended following distance: at least three seconds between the moment the car ahead passes a fixed object and the moment you pass it.
A vehicle moving slower than traffic that delays three or more vehicles in a rural area or on a two-lane highway must turn off wherever safe to let them pass.
Exception: snow removal and farm equipment on non-interstate highways with flashing lights visible for 500 feet. All slow-moving vehicles need a foot brake, turn signals, and the approved slow-moving vehicle emblem.
The car ahead passes a mileage sign. You count 'one-thousand-one, one-thousand-two' and you're already at the sign. You're following too closely: ease off until you reach three seconds, and stretch that further if it's raining.
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.
The three-second rule is the minimum recommended following distance, measured:
only at speeds above 55 mph
from when the car ahead passes a fixed object
as a fixed distance of three car lengths
from when you see brake lights ahead
Answer: from when the car ahead passes a fixed object
Count three seconds from when the lead car passes a fixed point.
