The California Vehicle Code says:

(d) A bicycle operated during darkness upon a highway, a sidewalk where bicycle operation is not prohibited by the local jurisdiction, or a bikeway, as defined in Section 890.4 of the Streets and Highways Code, shall be equipped with all of the following:

(1) 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.

I have a pretty bright Cygolite headlight, but it emits practically no light from the sides, if you look at a 90 degree angle you can't see any light at all from the headlight.

Is this strictly legal under the law? I do supplement with a blinky light that provides some side illumination (though I'm not sure you could see it from the sides at 300 feet from the bike), but I'm wondering if my headlight meets the letter of the law? If I'm ever in an accident, I don't want the other driver to be able to say "How could I have seen him, he didn't even have the headlight required by law!"

I've looked at a few other states but they didn't have any requirement for side visibility of the headlight.

  • Sounds like a slightly silly law to me! Isn't there a risk of unfocused headlamps (on any kind of vehicle) dazzling people around them?
    – GordonM
    Nov 7, 2012 at 23:52
  • I think that kind of phrasing is why the fairly similar Light and Motion Urban lights have little yellow prisms on the side. (but when riding on the hoods of my drop bars, my hands are in the way anyways.)
    – freiheit
    Nov 8, 2012 at 0:25
  • So, no light at a 90 degree angle. How about a 45 degree angle? 60 degree? 75 degree? Personally, I think a focused solid headlight and a 180º visible blinking headlight is ideal.
    – freiheit
    Nov 8, 2012 at 0:27
  • I would think it would be best to use a bright light pointing forward, and less bright secondary lights pointing to each side.
    – Kibbee
    Nov 8, 2012 at 13:34
  • I remember asking a police officer in a smaller Southern California city about bicycle lighting. He said generally, when the police determine fault in a night-time bicycle accident, they look for good visibility even if it is not strictly following the law (i.e. I could use an amber or green light in place of a white light), but inadequate lighting would always make the cyclist at-fault. I suspect having no side-visible lights would make the cyclist at-fault or partially at-fault for the accident, regardless of how bright the front light is. Nov 29, 2012 at 23:19

2 Answers 2


What the code is saying is that your headlight has to be visible on the sides. That's why most modern bicycle headlights have those little clear plastic channels on the side for the light to seep through and be seen from the side. ( The idea isn't to blind people GordonM )

Maybe it really reaches 300 feet, maybe it doesn't, the traffic police probably aren't going to pull you over and measure. But if you do get in a crash, the other person's lawyer may very well get clever and bring this up, so if you're worried about that, make sure your supplemental blinky light reaches far enough to satisfy the law.

The bottom line is that you want other bicycles and cars to be able to see you so that they don't hit you. If you are in an accident with a car or truck, there's a chance you'll be fatally injured and whether or not you adhered to the law won't mean anything. So be safe and make sure your lights are bright enough for other people to see you.

  • Most of the more expensive and brighter lights lack those side channels, they seem more common on the small AA battery powered lights. I have a Cygolite Metro light too and it has those side channels, but they barely emit any light at all. It seems ironic that the lights that meet the letter of the law barely illuminate the road, but the brighter lights that have great road illumination, don't have much (if any) side illumination.
    – Johnny
    Nov 8, 2012 at 0:27
  • 2
    @Johnny: I think a lot of the most expensive and brightest lights were intended by the manufacturer for off-road trail use.
    – freiheit
    Nov 8, 2012 at 0:29
  • 1
    Yes, the very bright and expensive lights are designed to help you see far in front of you much like a car headlight, especially off-road as freiheit said. When you're on the road they're meant to be supplemented with inexpensive flashing lights to help other people see you. Nov 8, 2012 at 0:30
  • Well, when I say "expensive", I don't mean the $400 eye searing HID light systems, but the $50-$150 300-600 lumen lights that are sold as "ideal for commuters" by local bike shops without any warning that they don't satisfy California Law. I happen to have a blinky because it also acts as my front reflector, but I had no idea that the blinky was required under the law (which I looked up after a minor bike accident and I wanted to make sure I was "legal"). In any case, I'm glad I asked here - thanks for the answers!
    – Johnny
    Nov 8, 2012 at 1:22
  • 1
    @mattnz: As long as one light meets the requirements, you'd be fine. The law requires "a lamp" but does not prohibit other lamps.
    – freiheit
    Nov 8, 2012 at 18:30

I think illuminating the sides of a headlight is a good idea. I use a Smart Polaris 220907 which has illuminated sides with my road bike an have made good experiences with it. When riding at night or dawn I always get seen early and well. For riding in really dark areas the light might not be enough, but for my use in an urban area with street lightning it is a fine position light.

Smart 220907

  • Sending light to the sides is definitely a good thing, but I don't want to downgrade to a less bright headlight to do it. Like you said, the light you have is probably a great "be seen" light with its 1/2 watt LED, but when I ran a 2W Planet Bike Blaze, I found it barely adequate for lightly lit suburban streets, and completely inadequate at night in the rain when the pavement seemed to soak up the light completely. I'm much happier with my Cygolite even if it doesn't have side illumination. (I use a Cateye LD-650-F for that)
    – Johnny
    Nov 16, 2012 at 20:01
  • You are right about the light getting soaked up. I rode through heavy fog the day before yesterday and at my usual distance, the light cone was not visible on the ground.
    – Bengt
    Nov 17, 2012 at 17:59

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