Motorcycle Headlight Modulator
From Wikipedia, the free encyclopedia
A Motorcycle Headlight Modulator (or simply Headlight Modulator) is an accessory device that oscillates the intensity of a daytime-illuminated motorcycle headlamp at 240 cycles per minute (4 Hz). The intensity is modulated between approximately 20% and 100% of normal steady-burning intensity. US and Canadian regulations require headlight modulators to include a light sensor that disables modulation when the ambient light level drops below a certain point. When this happens, the headlamps burn steadily.
[edit] Purpose
Motorcycles in the United States have since the mid-1970s been wired so as to operate the low beam headlamp whenever the engine is running. This is not required by any Federal regulation, but is rather a matter of voluntary industry policy. However, as increasing numbers of vehicles are equipped with daytime running lights, there is concern that the daytime-illuminated motorcycle headlamp is not especially conspicuous. Therefore, some motorcyclists install modulators in the belief that they increase motorcycle conspicuity in traffic, though to date, there are no data to support the notion that modulators reduce crashes involving motorcycles or otherwise improve roadway safety.
[edit] Laws about Headlight Modulators
In the United States, FMVSS 108 (Federal Motor Vehicle Safety Standards) (49 CFR Part 571.108 S7.9.4) allows motorcycle headlight modulation systems in all 50 states provided they comply with the standards set forth in this section. Furthermore, Title 49 USC 30103(b1) (US Code) prohibits any state from forbidding a system that conforms to FMVSS 108. The Code of Federal Regulations (CFR) is available at [1]. In the search enter 49 for Title, 571 for Part and 108 for Section. The paragraph that discusses motorcycle headlight modulation systems is S7.9.4. The United States Code (USC) is available at [2]. In the search enter 49USC30103
In Canada, Technical Standards Document No. 108, Revision 3 Lamps, Reflective Devices and Associated Equipment contains language nearly identical to the US code. The code is available at [3]. Scroll down the page (or use the search in your browser) and locate paragraph S7.9.4
