Flashing Rear Lights for Bicycles

CyclistI see more and more bicycles with flashing rear lights. Is this actually a better option or is it just a fad? I would like to know what the law is and if there is any research on the effectiveness of rear flashing red lights as opposed to lights that are just on all the time.

Personally, I find flashing lights distracting and more difficult to pinpoint where the bike is exactly and more difficult to judge it's speed compared to a light that is not flashing.

If flashing rear bicycle lights are more effective why don't all cars have flashing rear tail lights?

flashing rear lights for bicycles

Flashing Rear Lights

Let's take a look at the Motor Vehicle Act for a start:

Rights and duties of operator of cycle

183 (6) A cycle operated on a highway between 1/2 hour after sunset and 1/2 hour before sunrise must have the following equipment:

(c) a lighted lamp, mounted and visible to the rear, displaying a red light.

(7) Despite any other provision of this Act or the regulations, a cycle may be equipped with a flashing red light.

Might Not Be a Good Thing

Flashing lights do draw a driver's eye, and this may or may not be a good thing. As you observe, the drawing of attention is desirable, but the vehicle tends to move toward what the driver is looking at. It is also true that it is easier to track an object with a steady burning light. Perhaps the cycle should be equipped with both?

Study on Bicycle Lighting

The best study that I can find on bicycle lighting is from Europe: Requirements on Lighting (Light Intensity) and Reflectors of Bicycles

I've recently found another study: Lighting and Visual Information for Vulnerable Road User (VRU) Safety: An Introductory Review.

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I can agree that flashing red lights tend to draw the driver toward them. This was researched several years ago in the U.S. as well and consequently ended with the blue lights being used on police vehicles. Personally I would rather see a steady red light displayed at the rear of a cycle but I must give credit where credit is due and compliment cyclists that do use an illuminating device when cycling. Even a flashing red is better that no light at all.

pg 30 and 31 from the European study you recommended seems to have confirmed my belief that flashing rear lights are actually less effective and potentially dangerous.

"In summary it can be concluded that flashing bicycle lights are not necessary for agood conspicuousness. .........  From the rear, the flashing lights do not bring anyadditional benefits and in fact in rural areas even leads to a decrease in conspicuity.Flashing also has the following general disadvantages: it may confuse others, for example confusion with the lights from an emergency vehicle it may irritate others It makes other traffic participants less visible It makes it hard to judge the distance and path followed by the cyclist So, there seems little use for flashing and certainly should not be promoted."

interesting how people get caught up in fads and manufacturers make things to satisfy the fads rather than promote safety. As more and more people are riding bicycles there's going to be a lot of confusion with all those flashing lights, especially in busy places like Vancouver. I wonder what percent of riders are using them. Next time I'm in Vancouver I'll do a count.

In reply to by Anonymous (not verified)

I've owned one of these flashing LED bike lights for over 20 years. Battery life is a benefit.  Two AAA batteries are rated for 100 hours flashing, but only 30 hours in the steady mode. 

Thanks Tim for the comprehensive European studies. They even admit to the paucity of date, although it would be far less in this country. Coincidently I just received a rear led light for Father's Day. The 2nd of. The 1st wasn't installed years prior, but this mini is already. It is a steady beam.

 Yes, I have noticed while driving the tendency to 'targeting'-steering into, when it comes something new-out of the ordinary, that captivates attention, and that may be the downside of having a flashing light on the rear stay or seat post, amongst other reasons. It is annoying to paceline a fellow rider with a flasher. Good reason to not 'sit on', but I would rather not have them sit on all day and be rested when I am exhausted. Really we ought not to be obliged to have lights during the day; if only the world was perfect. And like vehicles with their day time runners deleted, they are the ones that get my attention. Which begs the question: if every vehicle has lights on 24/7 do we begin to 'not' see them. I am now noticing how numerous rear lights(even some on helmets) are now, and notice the riders that are not as visible. And that is cause for alarm, especially by the way in which the 2 wheeler is operated; the not very visible clothing worn; complications due to other vehicles obscuring the 2 wheelers presence. The choice of 2 wheelers is purposeful and pertains to engine powered 2 wheelers as well. 

I for one am against it as well as the flashing lights at the front of cycles.

Like others I applaud all cyclists and I am one too, for using lights on their bikes during the day and especially at night and in the dusk. However my problem is that with these flashing lights they cause me to have migraine, therefore I have to look away which could cause an accident and I have to just concentrate on the cyclist from above the chest.

What I do hate is the cyclist who insist on using the lights as strobe effect lights. I use an ordinary bright led light front and rear that is all plus high visibility clothing that is needed.

Be safe on the roads!