Massachusetts School Pupil Transport (7D) Certificate Practice Test

Keeping a safe following distance means using a time-based rule: two to three seconds behind the vehicle ahead under normal conditions. This amount of space gives you enough time to perceive a hazard, react, and brake to avoid a crash. The distance you need increases with speed because braking distance grows as speed rises, so you should allow more time if you’re moving faster. If conditions are poor—rain, snow, ice, fog, or limited visibility—add even more seconds to maintain a margin. Larger vehicles, or when following a bus, also require extra room because their stopping distance is longer. The other options aren’t appropriate because five seconds is not the standard baseline for normal driving, half a second doesn’t give you time to react, and distance clearly does affect stopping since stopping distance depends on speed and reaction time.