Today it was foggy, visibility was only slightly reduced, I already wear a high-vis on my bike but I am wondering if it is still worth me using my lights or is that overkill?

  • 11
    Why wait until it's foggy? I use a rear flashing red light all the time, even on sunny days. There is no such thing as overkill when it comes to visibility. Flashing lights are illegal in some jurisdictions, and steady lights allow drivers to judge your distance better, but there's nothing like a flashing light to make yourself seen. Sep 16, 2014 at 20:06
  • 5
    I think one close shave will be enough to convince yourself of the answer here. Battery life is cheap and it is amazing the number of drivers who will say "Sorry mate, I didn't see you" (google SMIDSY) even in good light. Give yourself every possible advantage.
    – PeteH
    Sep 16, 2014 at 20:32
  • 1
    Thank you for your comments and I do agree with you guys here. Sep 16, 2014 at 20:34
  • 1
    @Daniel R Hicks Bright strobe lights can be pretty annoying, especially when attached at a higher position. It's comparable with a headlight on a car which is pointing a upwards a bit too much. For a car driver your light may well be the only thing they can see for quite a large area. That means not being able to see the road edge not the pedestrian behind you if it isn't more brightly lit then you are. Don't overdo it, you need to be visible, but no more then the tail lights of a car. And flashing doesn't help, it only makes it harder to judge your position and speed.
    – AVee
    Sep 17, 2014 at 6:24
  • 1
    @Avee I agree that in darkness, especially on unlit roads, one should use lights, and many people do. And NL should be taken as a benchmark for safety, since it has the lowest incident rate (approx. together with Denmark). Of course I understand that this is mainly due to infrastructure, but I simply wanted to point out that some of the reactions here are (overly) cautious because of feeling unsafe. Are there any statistics to back up suggestions here to use lights in fog? Sep 17, 2014 at 7:49

5 Answers 5


I definitely recommend this. Running lights will make you more readily visible as the light will penetrate the fog to an extent. Reflectors and high-viz clothing will be somewhat less effective during foggy conditions. Use caution riding in foggy conditions as drivers may not see you until they are very close.

  • Not just a good idea, it's a legal requirement in some areas too! Sep 17, 2014 at 15:44

You should use lights in fog. On a car, you don't use high beams in fog (but you're supposed to use low beams (required) and fog lights (optional, but useful since they cast a low and wide beam which increases visibility) since they reflect back too much, but on a bicycle, your lights aren't that powerful for this to be a problem (and the distance they cover is less than a car light).

You should also be extra on edge and wear your high vis stuff, since your visibility is lower (and more importantly, people who are driving cars have lower visibility and aren't always very good at driving in fog).

  • 1
    Some modern bike lights are approaching and in some cases surpassing vehicle headlights.
    – Holloway
    Sep 17, 2014 at 9:37
  • @Trengot, but they are easy to point down a bit when in fog
    – Ian
    Sep 17, 2014 at 22:56

Many people run lights on a clear day for safety.

In the US by law a motorcycle must run lights all the time. Law was based on safety.

This is a related post
Does it make you safer to use lights during the day

Cars turn their lights on in the fog. Another answer was criticized for stating this is a no-brainier. But it is.

As for high beam versus low beam. A bicycle light is typically oriented as a low beam.


I always turn on my headlights even in the daytime for safety reasons, whether driving a car or riding a bike or motorcycle.

Many times I have tried to change lanes when visibility was limited and had to correct back into my lane because what I thought was a clear lane was actually occupied by a very hard to see vehicle coming up from my blind spot.

Many accidents could be avoided if everyone drove with their headlights on during limited visibility.


In Ohio, the way I read it, it appears that lighting falls under the generic vehicle lighting guidelines, so bicycles are required to act like cars in this one aspect (other rules explicitly state motorized vehicle or even "motorcycle").

So, lights are required when:

  • Between sunset and sunrise
  • Visibility less than 1000 feet
  • Windshield wipers are on (recent addition which I think is really dumb as we often have bright sunny days with occasional light sprinkles and lights are totally unnecessary, yet you'll be using the wipers). I've not yet seen a bicycle with wipers, so perhaps "raining enough that I'd use wipers if I had them" would be a good general rule too?
  • As a resident of Ohio myself, I don't think lights are required until it is pitch black, then they look at you crazy when you flash lights. /sarcasm
    – BPugh
    Jan 31, 2015 at 7:12
  • The old law in Ohio had the light usage period requirement at either (I can't remember for sure anymore) 1/2 or 1 full hour after sunset to the same 1/2 or 1 before sunrise. Basically when it was pitch dark. The new rules seem a little silly as it can be fairly light in the 15 minutes or so before sunrise on some days! Nevermind the fact that with all the light pollution we now have today from all the unnecessary roadway lighting, one could now easily ride/drive most streets without lights at all any time of night and be visible... Jan 31, 2015 at 19:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.