The clearance-lamp requirement is §393.11(a)(1) and Table 1. Two amber lamps go on the front of the vehicle and two red lamps on the rear, one on each side of the vertical centerline, each pair on the same level and as high as practicable, positioned to indicate the vehicle's overall width. Table 1 requires them on buses and trucks 80 inches or more in overall width and on semitrailers and full trailers of that width (front lamps also on truck tractors), and refers clearance lamps to footnotes 8, 9, 10, 15 and 17 for the vehicle-specific placement rules. §393.25(a) supplies the mounting standard: all lamps must be securely mounted on a rigid part of the vehicle, and temporary lamps must be securely mounted to the load. §393.9(a) requires every required lamp to be capable of being operated at all times.
A note on this page's address: an earlier version filed clearance lamps under §393.20. That section is [Reserved] — it holds no text — and the old address now redirects here.
Severity weight
Severity weight 2 in the Vehicle Maintenance BASIC for a missing clearance lamp — SMS Appendix A (version 3.21, revised May 2026) code 393.11A1-LCL, in the "Clearance Identification Lamps/Other" group alongside identification, side-marker, and license-plate lamps. That weight is specific to this finding, not to every subsection of §393.11: the generic §393.11 code ("no or defective lighting devices or reflective material as required") sits in the Reflective Sheeting group at 3, and the stop, tail, turn, and head lamp rows under the same section carry 6. The finding is most often paired with §393.9 (a required lamp inoperable) and the reflector rows of the same Table 1, so the citation rarely lands alone.
How it gets cited
Two common patterns: (1) clearance lamps on a bracket or body panel that is no longer rigid, so the lamp moves or hangs — a §393.25(a) mounting failure; (2) clearance lamps physically present but no longer marking the widest point, typically because a body modification moved the extreme width and the lamps stayed where the OEM put them.
How to prevent it
- After any body modification (sliding tandem, side rail addition, replacement bumper), verify the lamp positions still indicate the overall width.
- Confirm clearance lamps are securely mounted to a rigid part of the vehicle (§393.25(a)) during the §396.17 periodic inspection.
- Pre-trip lamp checks should include a quick visual confirmation that the side marker and clearance lamps line up with the vehicle corners, not the trailer-half corners.
How Roadworthy HQ helps
Vehicle Maintenance findings link to the vehicle record, attach to the corrective-action note from the §396.9(d)(3) repair certification, and surface on the audit binder so the finding and its remediation are documented together.