Headway is the time difference between the same point on the front vehicle and the rear vehicle. Which option best reflects this definition?

Headway is the time difference between the same point on the front vehicle and the rear vehicle. Which option best reflects this definition?

• A. Time difference between the front of the leading vehicle and the front of the following vehicle
• B. Time difference between the same point on the front vehicle and the rear vehicle
• C. Distance between vehicles
• D. Time interval between vehicle passages at a point

Answer: (B)

Headway is a time-based measure of how closely a following vehicle trails the vehicle in front, defined as the time gap between a specific point on the front vehicle and the corresponding point on the rear vehicle. Imagine marking the same point on each car, like the front bumper. When that point on the lead car passes a reference line, the identical point on the following car passes later; the time difference between those two moments is the headway. This focuses on how long it takes for the trailing vehicle to reach the position of the leading vehicle’s marked point, not merely the physical distance between cars. The other ideas describe either spatial spacing or the time between vehicles passing a fixed road point, which are related concepts but do not match the stated definition as precisely as using the same point on both vehicles.

Headway is a time-based measure of how closely a following vehicle trails the vehicle in front, defined as the time gap between a specific point on the front vehicle and the corresponding point on the rear vehicle. Imagine marking the same point on each car, like the front bumper. When that point on the lead car passes a reference line, the identical point on the following car passes later; the time difference between those two moments is the headway. This focuses on how long it takes for the trailing vehicle to reach the position of the leading vehicle’s marked point, not merely the physical distance between cars. The other ideas describe either spatial spacing or the time between vehicles passing a fixed road point, which are related concepts but do not match the stated definition as precisely as using the same point on both vehicles.