Trucking Laws · Nationwide · October 24, 2026

FMCSA Reopens Comments on Radar-Triggered Amber Trailer Warning Lights

The rear of a semi trailer with glowing amber lights on a highway at dusk — Illustration for this story. Not a photo of a specific location.

Should the back of a trailer flash amber when a vehicle is closing in too fast? The Federal Motor Carrier Safety Administration wants to hear more before it decides. The agency reopened public comments on Grote Industries' request to use radar-triggered pulsing amber lights on commercial vehicles, The Trucker reports.

FMCSA has not approved the request. Comments are open through Nov. 19.

How the system would work

According to The Trucker, Grote's system uses rear-facing radar to spot approaching vehicles and estimate how much time is left before they could reach the truck. When it sees a substantial risk, auxiliary amber lamps automatically pulse for up to four seconds.

Grote says the radar can detect vehicles about 200 meters back, or about one-tenth of a mile. The system works without any action from the driver.

Why an exemption is needed

Federal rules generally require exterior lights on commercial vehicles to burn steadily rather than pulse, The Trucker reports. Grote applied in December 2025 for a five-year exemption.

Why comments reopened

FMCSA first published the application for comment in February 2026 and later extended the comment period when the Commercial Vehicle Safety Alliance asked for more time, according to The Trucker.

One concern was whether drivers behind a truck might confuse the warning with brake lights. The original application described lamps that could flash before switching to steady red. Grote has since clarified that this warning uses pulsing amber only, and that steady red belongs to a separate brake-activated feature, The Trucker reports.

Grote also clarified that:

The exemption would apply to all commercial motor vehicles.
On doubles and triples, the system would go on the rearmost trailer.
Grote already has federal approval for a related brake-activated pulsing light system.

Before deciding, FMCSA must determine whether the technology would provide a level of safety equal to or greater than current rules.

How to comment

The Trucker says comments on Grote's supplemental information can be filed through Nov. 19 at Regulations.gov under docket number FMCSA-2026-0100. The agency is taking comments on the new information only, not reopening the whole application.