Roadside Inspection: Warning Device and Brake Stroke
At a Maine roadside inspection, a 33,000-lb GVWR straight truck with air brakes is pulled in. The driver holds a valid Class B CDL with no air-brake restriction and has a current medical card. The inspector drains the tanks and finds that the low-air-pressure warning never sounds as pressure falls below 60 psi. On the right rear axle, one brake chamber is a Type 24 clamp type, and the pushrod travel measures beyond the adjustment limit. The rest of the brakes look normal, and the truck has a current annual inspection sticker. The company dispatcher says the terminal is only 25 miles away and asks the driver to sign the inspection report and drive back for repairs. The driver must decide whether the vehicle can be moved, what the inspection report means, and what must be verified before the truck returns to service.
1. Can the driver legally and safely continue? Apply the out-of-service criteria.
Read the worked answer
No. An inoperative low-air-pressure warning device is an out-of-service defect, and a brake pushrod beyond the adjustment limit is also an out-of-service defect. The annual inspection sticker and the short distance do not override that. The driver should not sign and drive the truck 25 miles; a vehicle placed out of service must be repaired before it is moved under its own power, except as allowed by the enforcement officer for movement to a repair facility. The dispatcher cannot authorize the driver to ignore the order. The warning device is critical because the driver needs it to know when pressure is falling toward spring-brake application; the overstroke brake may not apply fully or may drag. Both defects affect stopping performance.
2. What documentation and repair verification should occur before the vehicle returns to service?
Read the worked answer
The inspection report should identify each defect and the OOS status. A qualified mechanic should repair the warning switch/buzzer circuit and the brake adjustment or foundation brake defect, then document the repair. Before return to service, verify the warning sounds before pressure drops below 60 psi, the compressor builds from 85 to 100 psi within the time limit, both static leak tests pass, the pushrod stroke is within the manufacturer's limit at 90 psi, and the brakes release without drag. The driver should review the repair documentation, sign the DVIR, and road-test the brakes at low speed in a safe area. The original annual inspection sticker is not proof that these defects were fixed.
3. What should the driver have caught in the pre-trip inspection, and what does this show about relying on a prior DVIR?
Read the worked answer
A proper pre-trip would include draining air pressure with the engine off and watching for the warning at or before 60 psi, listening for the buzzer, and checking that the spring brakes apply. The driver should also test for leaks, check the compressor build, and look at pushrod travel or at least watch for a brake that hangs or overheats. A prior DVIR only shows what the previous driver reported; it does not transfer responsibility. The driver must report defects and must not operate a vehicle with a known OOS condition. In this case, the warning test alone would have caught the defect before the roadside inspection.