Is the road wet or dry. 2 x higher speed 2 x longer reaction distance. To solve for time use the formula for time t ds which means time equals distance divided by speed.
60mph x 4 240 feet.
The reaction distance is affected by. When discussing the term Braking Distance it is typically more interesting to discuss the term Stopping Distance which also includes the reaction time. Establish the stopping distance. At 65mph you can travel almost 100ft per second.