What delay occurs with air brakes due to the time it takes air to flow through the lines?

The term for the delay that occurs with air brakes, due to the time it takes for air to flow through the lines, is indeed called brake lag. When air is applied to the brake system, it must travel from the compressor through the lines to the brake chamber. This process is not instantaneous, resulting in a slight delay before the brakes engage. Brake lag is particularly important for drivers to be aware of, as it affects stopping distances and response times when using air brake-equipped vehicles, such as school buses. Understanding this delay helps drivers anticipate how their vehicle will respond when they need to stop, allowing for safer driving practices.

The other terms associated with braking might refer to different issues: brake lock pertains to a condition where wheels lock up during hard braking, brake fade occurs when brakes overheat and lose effectiveness, and brake failure is the complete inability of the braking system to function. Each of these conditions reflects different mechanical or operational issues rather than the specific delay produced by air pressure in the braking system.