New Jersey Air Brakes Practice Test

In ideal conditions, how many feet would a truck or bus with air brakes traveling at 55 mph require to stop?

1. Less than 200 feet

2. About 250 feet

3. More than 300 feet

4. Over 400 feet

The correct answer is: More than 300 feet

In ideal conditions, a truck or bus with air brakes traveling at 55 mph typically requires about 300 feet to come to a complete stop. This distance accounts for several factors, including the time it takes for the driver to perceive the need to stop, the time it takes for the brake system to engage, and the actual braking distance. When a vehicle equipped with air brakes is moving at higher speeds, the stopping distance increases significantly due to the physics of deceleration. Air brakes are effective, but they still have limitations compared to hydraulic braking systems used in lighter vehicles. Moreover, larger vehicles like trucks and buses have more mass, which contributes to a longer stopping distance. In practical terms, while the exact stopping distance can be influenced by conditions such as road surface, tire composition, and the weight of the load being carried, the general guideline for a fully loaded vehicle indicates that it will take more than 300 feet to stop when traveling at 55 mph. This understanding is crucial for ensuring safety and maintaining appropriate following distances while driving larger vehicles.