Ask a Trooper: Headlight modulators are a motorcycle safety feature | Duluth News Tribune

what does headlight modulator do

Q: This isn’t a question but more of a need to get information out to the public concerning motorcycles. I ride a motorcycle and have recently added a headlight modulator for more visibility. I was recently riding my motorcycle with another motorcyclist with a headlight modulator. On two occasions, a motorist in the oncoming lane of traffic pulled over to the shoulder of the road, I guess thinking we were emergency vehicles. Would you mind informing the public on what a motorcycle headlight modulator is, how and why it’s used and what type of lights indicates an emergency vehicle?

I want to be safe riding my motorcycle, not a statistic from the uninformed public. Start seeing motorcycles, just know what you’re seeing!


Thank you for your service.

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A: I will answer your actual question: Would you mind informing the public on what a motorcycle headlight modulator is, how and why it’s used and what type of lights indicate an emergency vehicle?

Motorcycle headlight modulators are devices that make the headlight brightness go up and down, almost like a flashing light — but actual flashing lights are not legal on motorcycles. The modulating headlights are used to draw attention to the motorcycle, which is the same reason why headlights are required to be on at all times on a motorcycle in Minnesota.

The modulators are legal, but there are strict regulations on their use. The law is too extensive to be placed in this response. Anyone interested can easily find Title 49 of the Code of Federal Regulations (49 CFR Section 571.108) Paragraph S7.9.4 — Motorcycle Headlamp Modulation System online. I do see some motorcycles with modulators that are not conforming to that statute because they have headlights that are actually flashing, not just modulating the headlight.

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As for lighting on emergency vehicles, to me they are completely different than the modulators on motorcycles. Emergency vehicles generally have red or red and blue flashing lights to the front and/or rear, with yellow amber flashers to the rear in most cases. The lighting depends on what type of emergency vehicle you are talking about. Some emergency vehicles have flashing headlights used with the other lights, and I suppose that is what the similarity might be that you are referring to. Thanks for asking.

Sgt. Curt S. Mowers is a regional public information officer for the Minnesota State Patrol.