Answer :
Final answer:
When passing at highway speeds of 50 to 70 mph, a gap of at least 1500 feet is needed to ensure safety. This takes into account overtaking distance, vehicle lengths, and increased stopping distances at higher speeds. The calculation aims to promote road safety by considering multiple factors.
Explanation:
When passing at highway speeds of between 50 to 70 mph, you need a gap of at least 1500 feet to pass safely. This calculation takes into account several factors, including the time you need to overtake the vehicle in front of you safely, the length of your vehicle, the length of the vehicle being overtaken, and the speed differential between your vehicle and the one being overtaken. Assuming that you are trying to overtake a truck on the highway driving at 55 mph, and you increase your speed to 60 mph, the relative speed difference allows you to close the gap and overtake safely. However, considering the length of the truck (17 m), the length of your car (3 m), and the need for a safe distance both before starting to overtake and after completing the maneuver, a significant distance is required.
Additionally, the stopping distance at high speeds significantly impacts the needed gap for safe passing. The rule of one car length per 10 mph at high speeds is not conservative enough due to the rapid increase in stopping distances. This is because the kinetic energy that must be dissipated increases with the square of the speed, requiring more distance for safe stopping and maneuvering around vehicles on the highway.
Therefore, when considering the need to overtake safely at highway speeds, coupled with the distances required for safe stopping and maneuvering, a gap of at least 1500 feet provides a guideline that incorporates these variables and aims to enhance safety on the roads.
