Following distance — Idaho Permit Test

The three-second following distance rule is the minimum recommended safest procedure to use.

It is a minimum rather than a target, and it is what leaves room for the car ahead to stop hard.

The three-second following distance rule is the minimum recommended safest procedure to use

To use the three-second rule, choose a fixed object such as a sign or tree ahead of the car in front, and as that car passes it count off three seconds.

Counting off a distance works at any speed, which is why it is a count and not a number of car lengths.

Choose a fixed object, such as a sign or tree ahead of the car in front of you

If it takes at least three seconds before you pass the object, you have enough distance for a sudden stop.

The three seconds is the reaction time plus the braking, which is what a sudden stop actually costs.

If it takes at least three seconds before you pass the object, you have enough distance for a sudden stop

At high speeds or in bad weather you need to increase your following distance, and in bad weather the three seconds should be increased several times.

Wet pavement roughly doubles the braking distance, so a gap that was enough in the dry is not.

In bad weather, the three seconds should be increased several times to give an extra margin of safety

Tailgating, which is driving too close to the car ahead, is a common cause of crashes. When following another car you must leave enough space to stop in any situation.

The car in front can stop faster than you expect if it hits something, and then the gap is all you have.

“Tailgating” (driving too close to the car ahead) is a common cause of crashes

Be sure your brakes are in good shape and know how quickly they will stop you under any conditions, testing them often and particularly when the road is wet, icy or snowy.

Brakes behave differently on a wet road, and the time to find out is not the moment you need them.

Test them often, particularly when the road is wet, icy or snowy

To avoid a collision you need time to react to danger, so keep plenty of space between your car and others on all sides.

A car with space around it has somewhere to go. One boxed in has only the brakes.

To avoid a collision, you need time to react to danger. Try to keep plenty of space between your car and others on all sides

Stay in the middle of your lane and always make sure there is enough room ahead to stop or pass safely. If a car follows too closely, slow down and let it pass.

Speeding up to get away from a tailgater puts you closer to whatever is in front, which is the wrong end to be short of room.

If a car follows too closely, slow down and let it pass

What is Idaho's minimum recommended following distance rule?

Three seconds. It is a minimum rather than a target, and it is what leaves room for the car ahead to stop hard. July 2026 Idaho Driver's Handbook, p.79: “The three-second following distance rule is the minimum recommended safest procedure to use”