§393.82 requires every CMV to be equipped with a speedometer indicating vehicle speed in miles per hour and to maintain accuracy of ±5 mph at 50 mph. The rule is short, but it is one of the easier findings for an inspector to cite — the inspector compares the dashboard reading against a calibrated source as the vehicle moves.
Severity weight
Severity weight 1 in the Vehicle Maintenance BASIC. Notice-level by SMS weighting, but the cite pairs poorly with any §392.2 speeding finding — an inspector who finds both will note that the driver had no working means to know the speed.
How it gets cited
The common pattern is a non-functioning speedometer driven by a failed sensor, a bad cluster, or a CAN-bus fault — the gauge sits at zero or buries the needle. Less common: a working gauge that reads 5+ mph off after a tire-size change without recalibration.
How to prevent it
- After any tire-size, gear-ratio, or transmission swap, recalibrate the speedometer.
- Treat a dead speedometer as a same-day repair, not "we'll get to it" — drivers cannot self-regulate speed without it.
- Verify speedometer accuracy at every §396.17 annual inspection.
How Roadworthy HQ helps
A speedometer citation shows up in Roadworthy HQ as part of the inspection it came from, not as a record of its own: the app does not store individual violation codes. Log the roadside inspection on the vehicle's Inspections tab: date, state, level, driver, the number of violations, and whether it was out-of-service. For an out-of-service inspection the 15-day §396.9(d)(3) repair-certification countdown stays on that tab until you enter the certification date. The rule's 15 days cover every violation on the report, not only out-of-service ones, so for a non-OOS inspection that date is yours to track. The repair itself goes in the vehicle's maintenance log: date, type, what was done, who did it, and cost. DVIRs are logged per vehicle with the defect described in your own words, and a defect marked safety-affecting that is logged without a repair certification sends a critical alert.