At what speed must a driver be able to stop if traveling at 60mph?

To determine the stopping distance for a vehicle traveling at 60 mph, it's important to consider both reaction time and braking distance. Typically, at highway speeds like 60 mph, several factors come into play, including the driver's reaction time and the vehicle's braking performance.

Reaction time—how long it takes a driver to respond to an obstacle—averages around 1.5 seconds. During that time, the vehicle continues to travel at full speed. The distance covered during the reaction time can be calculated as follows:

1. Reaction Distance:

   • Speed (in feet per second) = 60 mph * (5280 feet/mile)/(3600 seconds/hour) = 88 feet per second.
   • Reaction distance in 1.5 seconds = 88 ft/s * 1.5 s = 132 feet.

2. Braking Distance: The braking distance at 60 mph is generally estimated using the formula (speed in mph)²/20, which gives an approximation of the braking distance in feet. For 60 mph, this would be:

   • (60 mph)² / 20 = 3600 / 20 = 180 feet.

3. **Total Stopping