Bicycle light maximum brightness?

I saw this question on a local bicycle discussion list:

Is there a legal limit to how bright a bicycle light can be in the Bay Area measured in lumens?

3 bicycle headlights

Equipment requirements for bicycles are addressed in California Vehicle Code 21201. It says only that bicycles operated at night must be equipped with “A lamp emitting a white light that, while the bicycle is in motion, illuminates the highway, sidewalk, or bikeway in front of the bicyclist and is visible from a distance of 300 feet in front and from the sides of the bicycle.”

There’s just a (poorly defined) minimum brightness; no maximum brightness is specified.

In California, almost all traffic laws — including bicycle laws — are regulated at the state law to provide for uniformity. Among the more notable exceptions are sidewalk riding and registration requirements, which may be regulated at the local level.

Do any American states specify anything beyond a minimum brightness for bicycle headlights? Internationally, I know only that the German StVZO law and Dutch DEKRA NL standards limit front light brightness to avoid dazzling people in front of them.


  1. Is there an upper limit for motor vehicle lights, measured in lumens? If so, would bicycles be subject to those regulations because they’re vehicles?
    There’s been SO much done over the last century to improve auto headlights without blinding oncoming traffic. It’s frustrating the method for “improving” most bicycle headlights is to just pump out more lumens. More frustrating is the number of fellow cyclists who refuse to dim or at least partially cover their lights when passing opposing cyclist traffic.

  2. Is there an upper limit for driver stupidity? – What kills more, bright lights, or bad drivers? – apply laws where they are liable to do the most good.

  3. Excellent question, Mark. But here’s something to consider- is cyclist safety proportional to how bright his or her lights are? How about flashing lights? If my attention as a driver or cyclist is dominated by one individual’s lights is the safety of everyone on that road or trail greater or lesser?
    Relying on brighter lights or more rapidly flashing strobes to increase the safety of the person using those lights is as logical as getting larger and larger SUVs for occupant safety- without any concern for anyone else’s safety.
    The Germans and Dutch have it right. For use on public streets there are regulations on lights to increase all users’ safety.

  4. too many fools think they may blind on coming traffic with lighting made for off road night riding… using these lights is stupid and only causes a dangerous condition… but the idiots believe brighter is better… maybe some adjustment of their narcissistic idiocy is called for…

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