What is the maximum allowable air leak rate for a straight truck or bus air brake system with the engine off and brakes released?

The maximum allowable air leak rate for a straight truck or bus air brake system with the engine off and brakes released is indeed 2 PSI per minute. This standard is set to ensure safety and reliability in the braking systems of commercial vehicles. A leak rate greater than this limit could indicate a potential issue within the air brake system that could compromise its effectiveness when needed.

Maintaining a low air leak rate is critical because air brakes depend on a consistent supply of compressed air to function properly. If there is too much air loss, the brakes may not engage effectively, resulting in longer stopping distances or even brake failure. By limiting the air leak to 2 PSI per minute, the regulations aim to ensure that the braking system remains responsive and that commercial vehicles can operate safely on the road.

This standard is part of the broader safety measures in place to help prevent accidents and ensure that drivers maintain their vehicles in good working order.