CDL School Bus Endorsement Practice Exam

The safety valve of school bus air brakes is set to open at 150 psi to ensure proper safety and functionality of the braking system. This pressure is designed to release excess air pressure to prevent over-pressurization in the brake system, which could lead to brake failure or other dangerous situations. Setting the safety valve to this level allows for a balance between adequate braking performance and the prevention of damage to the air brake components. Understanding the significance of this pressure threshold can help maintain the integrity of the air brake system, ensuring that it operates safely and effectively when transporting passengers. It's important for drivers and technicians to be familiar with this specification, as it plays a crucial role in vehicle safety and compliance with regulations.