Three paragraphs make up the stop-lamp rule. §393.11(a)(1) and Table 1 require two red stop lamps at the rear of the vehicle, one on each side of the vertical centerline, at the same height, as far apart as practicable, and between 15 and 72 inches above the road surface — on buses, trucks, truck tractors, trailers, and converter dollies alike. §393.25(f) requires those lamps to be activated upon application of the service brakes (they need not activate when the emergency feature of the trailer brakes is used, or while a stop lamp optically combined with a turn signal is signalling a turn). §393.9(a) requires every lamp Table 1 calls for to be capable of being operated at all times, so a stop lamp that stays dark under braking fails both paragraphs. §393.11(c) adds that no CMV may carry an amber stop lamp or a lamp optically combined with one.
A note on this page's address: an earlier version filed stop lamps under §393.13. That section is the retroreflective-sheeting retrofit rule for trailers manufactured before December 1, 1993 and says nothing about stop lamps. The old address now redirects here.
OOS criteria
All stop lamps inoperative — every stop lamp on the unit dark — is an out-of-service condition under the CVSA North American Standard Out-of-Service Criteria. A single inoperative stop lamp is a roadside citation but generally not OOS by itself. The criteria are a CVSA publication updated each April 1, not a CFR section.
Severity
Severity weight 6 in the Vehicle Maintenance BASIC — SMS Appendix A (version 3.21, revised May 2026) lists §393.25(f) "Stop lamp violations" in the Lighting group at 6, the same weight as a missing stop lamp under §393.11. The finding compounds when the same inspection also cites the driver under §396.13 — the driver must be satisfied the vehicle is in safe operating condition before driving it, review the last driver vehicle inspection report, and sign it — because both findings land on the carrier's record.
How to prevent it
- Lighting devices and reflectors are one of the eleven items every DVIR must cover (§396.11(a)(1)(iv)). Check the stop lamps with a helper on the brake pedal, at pre-trip and post-trip.
- Before the vehicle moves again, the carrier must repair any listed defect likely to affect safe operation and certify the repair on the report (§396.11(a)(3)(i)–(ii)); the next driver reviews and signs that report under §396.13(b)–(c).
- LED replacement lamps last longer and fail less abruptly than incandescent — a common upgrade for owner-operators.
- Trailer-end stop lamps depend on the 7-pin cable. Inspect the cable connector at every coupling.
How Roadworthy HQ helps
A stop-lamp 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.