Stopping at 55 mph using a 4-second safety cushion

• A. 4's safety cushion, 320ft traveled, 340ft distance to stop
• B. 4's safety cushion, 240ft traveled, 210ft distance to stop
• C. 5's safety cushion, 400ft traveled, 340ft distance to stop
• D. 3's safety cushion, 360ft traveled, 380ft distance to stop

Answer: (A)

Stopping distance equals reaction distance plus braking distance. At 55 mph, the vehicle covers about 80 ft each second, so a four-second safety cushion yields a reaction distance of roughly 80 × 4 ≈ 320 ft. After braking begins, the braking distance from 55 mph is typically around 340 ft with moderate deceleration. So the scenario should show about 320 ft traveled during the four-second cushion and about 340 ft to stop. That matches the option listing those two distances. The other choices either use the wrong cushion time or incorrect distance values for the reaction or braking phases.