What is the additional stopping lag distance required for air brakes at 55 mph?

At a speed of 55 mph, the additional stopping lag distance required for vehicles equipped with air brakes is important to understand for safe operation. Stopping lag distance refers to the space needed for a driver to react and begin the braking process after recognizing the need to stop.

For air brakes, the stopping lag distance at 55 mph is approximately 32 feet. This distance is calculated based on the time it takes for the driver to react and the speed of the vehicle. The lag time is typically considered to be around 3/4 of a second for a trained driver, and when traveling at 55 mph, the vehicle covers a significant distance during this reaction time, contributing to the overall stopping distance.

Recognizing this distance helps drivers operate their vehicles safely, as it highlights the need for maintaining a safe following distance and being aware of the time necessary to bring a heavy vehicle to a complete stop. In contrast, other distances provided in the options do not represent the standard additional stopping lag distance for air brakes at this speed.