It's time they did. But they didn't do anything about it. In 1987, ATA again requested a rule on this vital issue. They still haven't taken action. It's time they did.
Brake linings rub against brake drums and generate the force needed to stop a truck.
And like sandpaper, brake linings wear out and must be replaced. This means it is impossible to determine the friction level of a worn lining that needs replacement. Linings with high friction levels will abrade the brake drums more rapidly. Low friction linings require harder application of the brakes for a given level of performance, but they do not wear out as quickly and are easier on the drums than those having high friction levels. Appropriate friction levels are determined by the individual truck's braking system design and real-world operations.