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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.

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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 '12 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 '12 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 '12 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 '12 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. –  James Schek Nov 29 '12 at 23:19

3 Answers 3

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.

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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 '12 at 0:27
@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 '12 at 0:29
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. –  hillsons Nov 8 '12 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 '12 at 1:22
@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 '12 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

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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 '12 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 '12 at 17:59

The bicycle law here in Ohio is the same as California's...300 feet visibility to the sides. But the police will tell you that the front, rear and wheel reflectors reflect a vehicle's headlights probably better than most battery run lights would. After all, the reflector is reflecting "light!" Probably a brighter light form the vehicle lights than the battery light of the bike. The police likely have bigger fish to fry than to stop dozens of bicyclists every evening because their bicycle light ( if they even have one ), doesn't meet the side lighting requirement. A small piece of reflective tape on the sides of the light or on the forks, in a side position on the bicycle, or on your helmet should also meet the requirement for side lighting at night. Some bicycles have the reflectors on the wheel spokes that meet the side view lighting requirements. ( The tape would be much lighter in weight! ) The reflectors I've seen on bicycles at night from the side view, are much brighter than any small sliver of light emitted by the cut out side view of a headlight. And there is a lot of the time when your arms will block the side view of the headlight when you're on the brake hoods. I notice other bicycles with reflecters from the side at night at distances much greater than 300 feet...usually twice that distance or more, plus they're moving which attracts attention. The reflecters are reflecting light that's usually much greater than the amount of light produced by a standard battery headlight.

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The California Vehicle Code section quoted above seems quite clear that the lamp is required to emit light to the sides (visible from 300 feet). Lighting and reflectors are treated separately with different requirements for each. I don't see any provision in the CVC that would allow reflectors to be substituted for lights. –  Johnny Nov 26 '12 at 6:25
Of course, how many bikes in California have a light at all? A cop is unlikely to stop you on this point if you have good lighting otherwise, and (for my money) the on-spoke reflectors are far more effective than lights in making your bike visible to motorists from the side. –  Daniel R Hicks Nov 26 '12 at 13:07
I'm not concerned with being stopped a cop - in my city they routinely ignore bikes riding at night with no lights or reflectors at all. I'm more concerned with making sure I'm meeting at least minimum legal standards so if I'm ever in an accident, the other driver doesn't gain a legal advantage by pointing out that I didn't have proper lighting. Side reflectors may be helpful as a supplement to lighting and in some cases more effective, but there are many situations where reflectors are going to be less effective than lights. –  Johnny Nov 26 '12 at 17:36
If you're really that worried about it, drill holes in the side of your light and fasten in place bits of clear plastic. Or just get a couple of penlights and fasten them to your bars, facing each side. –  Daniel R Hicks Nov 28 '12 at 2:46
@Johnny Good point. "At fault" for the purposes of an accident, insurance, or liability often will use strict legal definitions rather than "practical" application of the law in order to avoid having to pay money. –  James Schek Nov 29 '12 at 23:16

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