So daytime running lights actually improve bicycle safety?
Should they be flashing or steady? We will investigate in this video. As much as we
don't like to think about it, cycling is considerably more dangerous than driving.
When evaluated per kilometer traveled, the risk of serious injury and death while cycling is about 10
times higher than while riding in a car. On average, about half of cycling incidents are single bicycle
crashes, usually caused by loss of control, poor road conditions or mechanical failure. The other
half are multi-party incidents, those involving pedestrians, other cyclists and, more importantly,
motor vehicles. Let's review some of the more common motor vehicle related incidents. The most
severe of these collisions occur when motorists overtake cyclists from behind. The most common site
for car bike crashes is at intersections, and these include motorists not yielding to cyclists at stop
signs, or during left turns and right turns. In most of these crashes, motorists indicated they didn't see
the cyclists in time. Does being more noticeable actually make a difference? Could daytime running
lights be the answer? To find out, researchers in Denmark selected 4000 volunteer riders,
half of whom were given front and rear permanent running lights while the other half, acting as
the control group, were to ride without them. The running lights were attached to the front and rear
forks. Powered by magnets, they generated a small flash (less than 10 lumens) as the wheels rotated.
This also meant they stopped flashing when the bicycle stopped moving. At the end of the 12-month
test period, a 47% reduction in multi-party crashes was recorded by the group using daytime running
lights, despite the relative low intensity of the flashes and issues related to immobile cyclists.
This clearly demonstrates the benefit of such devices. Should running lights be flashing or
steady? Laws and regulations vary from country to country or even between areas in a country.
Flashing lights are illegal in Germany, for example, while some places like the United Kingdom regulate
the flashing rate. You'll have to check specifics if you're planning to cycle in other countries.
When legal, flashing lights do have definite advantages. Depending on frequency and duration,
flashes can be perceived as being brighter than a steady light of identical intensity, thus making
the cyclists more visible. It also extends battery life because flashing uses much less power than
a steady beam. The Broca-Sulzer effect is a phenomenon where flash duration between 50
and 100 milliseconds is perceived by the human brain as being significantly brighter than it
really is. We started using a rear daytime visible light during our 2019 East Coast Greenway tour.
Florida having the highest incidence of cyclist crashes per population in the
United States, we felt it wise, in addition to wearing our reflective vests. We opted for the
Brontrager Flare R, especially designed as a daytime running light. This model
has now been replaced by the more powerful Flare RT, which is also smaller and lighter.
The flashing pattern uses 50 and 100 ms bursts to optimize human perception. It also uses a
reflector and lens to concentrate the available light into a narrower and more powerful beam.
Researchers at Clemson University in South Carolina use the Bontrager RT light to study
the minimum distance required by motorists to identify a cyclist on the side of the road.
Riders with flashing lights were identified 85 meters earlier, increasing motorist reaction time
by about 5 seconds. During our last 4 years using the Flare, we particularly appreciated
its long battery life and its distinctive and powerful flashing pattern. Note that it's important
to orient the lens properly during installation as this light beam is relatively narrow and a slight
misalignment will reduce its visibility over a longer distance. Those using the Brompton rear rack
to carry high loads may need an alternate mounting setup as a seat post view may be obstructed.
At maximum daytime setting, the latest RT provides 90 Lumen flashes for 6 hours. While touring, we
ran them constantly and recharged them daily (using the provided micro USB cable) and never
ran out of power while riding. The RT is very light at 40 grams and is extremely waterproof rated IPX7.
We recently decided to use a front daytime visible light as well. Available space on the
Brompton handlebar is limited, especially on our pre-2017 M bars. The mounting straps of
our handlebar bag further restrict the situation. Gilbert solved the problem by installing a
Ravemen FR 160 to a stem Garmin adapter mount. This light has its own adapter mount on its top surface,
therefore letting us use both the Garmin GPS and the light without taking up additional space.
Note that a low-cost conversion kit is available for those who favor Wahoo cycle computers. The FR 160
has a wide angle of view and six different light modes, three fixed and three flashing. The strongest
flash, mainly designed for daytime, providing 160 lumens for up to five hours on a single charge.
It's 180 degree wide angle lens provides good side visibility although it somewhat dilutes
the overall illumination. The lack of contrast is particularly noticeable on bright sunny days.
Designed to be seen rather than to see by, it's 50 lumens in high steady mode might
be insufficient as a main source of light for night riding, but could serve in an emergency.
The 55 gram device is waterproof at IPX6 and comes with the USB-C charging cable. It's low
profile and dual Garmin Mount make it a good solution when cockpit space is limited. Daytime
running lights have been standard on motorcycles and cars for many years. Although not mandatory
for cyclists, they have been proven to reduce the risk of multi-parted crashes by almost 50%.
Using them in a high risk environment is probably one of the best low cost-high return investments
we can make next to wearing a high visibility vest. For maximum visibility in bright daylight, we would
suggest 100 lumens or more, but as demonstrated in the scientific studies, even a relatively small
flashing light can make a big difference. Are you using a daytime visible light? Which model have
you selected? Let us know in the comments. We are Pam and Gilbert of 2Bikes4Adventure.