A good rule of thumb for following distance at speeds below 40 mph is to allow at least one second for each how many feet of vehicle length?

The correct answer is based on a common guideline used to determine safe following distances for vehicles, particularly for larger vehicles like school buses. The rule of thumb states that for every 10 feet of the vehicle's length, a driver should allow at least one second of following distance at speeds below 40 mph.

Given that typical school buses range in length from about 30 to 40 feet, employing this rule of thumb helps ensure adequate space to react if the vehicle in front needs to stop suddenly. The one-second rule provides reassurance that the bus driver has enough time to respond to any sudden changes in traffic conditions, thereby enhancing safety for both the bus driver and the passengers.

By focusing on the measurement of 10 feet, this rule aligns well with the standard practice of maintaining a safe distance according to vehicle size and speed. It is crucial for bus drivers, who transport children and may need extra time for stopping, to adhere to this guideline to prevent accidents on the road.