New Jersey Air Brakes Practice Test

Which of the following statements is true about air brake systems?

1. They are quicker to activate than hydraulic brakes

2. They maintain pressure without needing constant input

3. They can stop a vehicle more gradually

4. They are less complex than hydraulic systems

The correct answer is: They maintain pressure without needing constant input

Air brake systems are designed to maintain pressure without requiring constant input, which is a significant advantage. Once the air is compressed and stored in the system's tanks, it can be used to apply the brakes multiple times without needing to constantly pump air into the system. This stored air allows for consistent and reliable braking performance, particularly in large vehicles like trucks and buses. In contrast, hydraulic brake systems rely on the continuous movement of brake fluid from the master cylinder to the brake components, which can lead to variations in pressure and performance if there are leaks or inconsistencies in fluid levels. The ability of air brake systems to hold pressure over time ensures that they are ready to respond when the driver applies the brakes, providing reliability and safety. The other statements, while reflecting certain aspects of air brakes, do not accurately characterize the primary function of the system. For example, air brakes do require a system to be activated, and hydraulic brakes can often provide rapid stopping power. In terms of gradual stopping, air brakes can be modulated, but hydraulic systems can also achieve smooth stops effectively. Furthermore, hydraulic systems are typically simpler in terms of components because they do not require the extensive air supply and storage systems that air brakes need.