Following distance, trucks and motorcycles

Key points

1. Use the three second rule: if you pass the fixed point before you finish counting, you are too close.

   Source: Handbook p. 48

   “If your vehicle passes the point before you finish your count, you are following too close to the vehicle in front of you.”
   Rhode Island Driver's Manual, Handbook p. 48

2. In bad weather or road conditions, add another second or two to your following distance.

   Source: Handbook p. 48

   “When driving under adverse weather/road conditions, be sure to add another second or two to your following distance.”
   Rhode Island Driver's Manual, Handbook p. 48

3. The stopping rule: you should be able to stop within 4 seconds of a fixed object ahead.

   Source: Handbook p. 48

   “A safe stopping distance within four (4) seconds gives you the opportunity to stop safely without colliding with a person, vehicle or object.”
   Rhode Island Driver's Manual, Handbook p. 48

4. Search the 12 to 15 second target area ahead for intersections, driveways and parked vehicles.

   Source: Handbook p. 47

   “Evaluate your front zones in the 12-15 second target area (this refers to the area you will be in after you have traveled for 12-15 seconds) by searching intersections, driveways, and parked vehicles”
   Rhode Island Driver's Manual, Handbook p. 47

5. If you are being tailgated, change lanes; never speed up or slam on your brakes.

   Source: Handbook p. 35

   “If you are being tailgated, change lanes. Never speed up because you will be tailgated at a higher speed. Never slam on your brakes.”
   Rhode Island Driver's Manual, Handbook p. 35

6. Big trucks are 4 times more likely than other vehicles to get into collisions.

   Source: Handbook p. 49

   “big trucks are four (4) times more likely than vehicles to get into collisions.”
   Rhode Island Driver's Manual, Handbook p. 49

7. Stay at least 50 feet behind a truck; you are far enough back when you can see its side mirrors.

   Source: Handbook p. 49

   “Stay at least 50 feet back if you expect the driver to see you. You know you have enough distance behind a truck or semi-tractor-trailer when you can see the side-view mirrors of the truck you are following.”
   Rhode Island Driver's Manual, Handbook p. 49

8. Motorcyclists often slow without a brake light, so allow 3 to 4 seconds of following distance.

   Source: Handbook p. 46

   “Motorcyclists often slow by downshifting or merely rolling off the throttle, thus not activating the brake light. Allow more following distance, say three (3) to four (4) seconds.”
   Rhode Island Driver's Manual, Handbook p. 46

9. A motorcycle may look farther away than it is, so assume it is closer when turning.

   Source: Handbook p. 46

   “When checking traffic to turn at an intersection, assume a motorcycle is closer than it looks.”
   Rhode Island Driver's Manual, Handbook p. 46

Numbers to know

3 questions from the Rhode Island practice test

1. 1. How does the Rhode Island three second rule measure following distance?

   1. Use the speedometer to hold a fixed number of feet
   2. Measure three car lengths with a tape measure
   3. Wait until the vehicle ahead changes lanes
   4. Count until your vehicle reaches a fixed point passed by the vehicle ahead
   Show answer

   Count until your vehicle reaches a fixed point passed by the vehicle ahead. The three second method uses a fixed roadside reference. When the vehicle ahead passes a sign, pole, tree, overpass, or pavement line, the following driver starts counting. Reaching that same point before the count ends means the gap is too short, so the driver should drop back and count again. Car lengths and fixed feet change meaning as speed changes, and a lane change is not a reliable measurement event. The cue is point, count, compare: select a landmark and let time, rather than guesswork, set the cushion.

2. 2. What following-distance adjustment is recommended during adverse weather or road conditions?

   1. Reduce the gap because slower traffic needs less space
   2. Add another second or two to the normal following distance
   3. Keep exactly three seconds in every condition
   4. Follow within one second when visibility is limited
   Show answer

   Add another second or two to the normal following distance. The normal three-second method is a starting point, not an unchanging measurement. When weather or the road surface is adverse, the manual says to add another second or two. That extra cushion provides more time when traction or visibility is reduced. Cutting the gap makes a sudden stop harder, and holding exactly three seconds ignores the stated adjustment. Use a fixed roadside object to count the interval, then increase it when rain, snow, ice, or another hazard is present.

3. 3. Why should a driver leave substantial space behind a large truck or semi-tractor-trailer?

   1. Tailgating can be fatal, and at least 50 feet helps the truck driver see you
   2. The truck's legal speed requires every car to stay 100 feet back
   3. Following close prevents airflow from moving the car
   4. A truck's rear blind spot is always exactly 20 feet
   Show answer

   Tailgating can be fatal, and at least 50 feet helps the truck driver see you. Large trucks have substantial blind areas, and a close-following car may disappear from the driver’s view. The manual warns that tailgating a semi-tractor-trailer can be fatal and recommends staying at least 50 feet back when you expect the driver to see you. The distance is not a universal legal speed rule, and close positioning does not control airflow safely. A useful visual check is whether you can see the truck’s side-view mirrors while maintaining space.

Source: the Rhode Island Driver's Manual, VII. Systems for Safe, Courteous, and Defensive Driving. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.