FMCSA Reopens Comment on Grote's Flashing Warning-Lamp Exemption
Grote Industries applied in December 2025 for a five-year exemption from 49 CFR 393.25(e), the rule requiring steady-burning exterior lamps on commercial motor vehicles. The exemption would let carriers use auxiliary warning lamps tied to Grote's Rear-End Collision Warning (RCW) system, which uses rear-facing radar to estimate time-to-collision and flash a warning when a vehicle closes in fast.
FMCSA's original February 2026 notice said the lamps would flash or strobe, then switch to steady-burning red. The Commercial Vehicle Safety Alliance objected, warning that following drivers could mistake steady red for braking. FMCSA staff then met with Grote for clarification.
Grote now says the RCW lamps pulse amber for up to four seconds and do not turn steady red on their own. Steady red only appears when the separate brake-activated lamp function takes over, which has priority if braking and an RCW event happen together. Grote also confirmed the radar detects vehicles at roughly 200 meters, the system requires no driver input, and on combination vehicles it would sit on the rear-most trailer.
FMCSA has not decided on the exemption and is limiting new comments to this supplemental information.
What's next
- Comments on the supplemental information are due November 19, 2026.
- FMCSA will review comments before ruling on the exemption request.
All sources
- Notice: Parts and Accessories Necessary for Safe Operation; Application for an Exemption From Grote Industries, LLC — Federal Register (Federal Motor Carrier Safety Administration), 2026-10-20
