FE Civil Engineering Exam Prep

Answer: B - AASHTO assumes that the height of a driver’s eye and the height of an object above pavement are 42 inches and 24 inches (respectively) when developing recommendations for minimum stopping sight distances. AASHTO’s recommended distances are a conservative estimate of how long it will take a driver to perceive a situation exists that will require them to stop, apply the brakes, and come to a complete stop. The stopping site distance is an important safety consideration to assure that drivers have a continuous length of visible roadway.