§393.71 supplements §393.70 with the requirements specific to driveaway-towaway operations and to longer combinations (doubles and triples): tow-bar dimensions and mounting, saddle-mount requirements, safety devices on each tow-bar and saddle-mount connection, and the precise geometry of the inter-trailer connections in a multi-trailer combination.
Severity weight
Severity weight 5 in the Vehicle Maintenance BASIC. The findings rarely appear in single-trailer fleets; they cluster in driveaway operators and in the small subset of carriers running doubles/triples on permitted lanes.
How it gets cited
For driveaway-towaway: tow-bar fastenings that have loosened in transit, saddle-mount upper structures that show fatigue cracking, missing safety chains across the connection. For doubles/triples: converter-dolly hitches that do not match the trailer kingpin dimensions or are mis-pinned, missing or unsecured pintle hooks at the lead trailer's rear.
How to prevent it
- Driveaway connection inspection at every stop — tow-bar fasteners, saddle-mount cup, safety devices. The vibration profile of towed vehicles is harsher than purpose-built combinations.
- For doubles/triples: standardize converter-dolly kingpin dimensions across the fleet to avoid mismatched coupling in mixed-trailer operations.
- Drivers running their first double/triple need formal §380.503 training, not on-the-job instruction.
How Roadworthy HQ helps
§393.71 findings link to the connection-specific equipment record (tow-bar, saddle-mount, converter dolly) and to the driver-training log so configuration-specific findings drive configuration-specific corrective action.