On 4/19/2019 3:43 PM, John B. Slocomb wrote:

snip

The Odense study, for example, tested the effectiveness of tiny
little, "flea powered" (to use Jay's description) flashing lights
mounted at hub level at both front and rear wheels. Yet today we are
told that one must use blindly bright lights to be safe.

The ultimate results of the Odense study seems to have been the change
in a Danish law to allow the use of always on DRL's which, apparently,
had previously been forbidden in Denmark.

People with an agenda will always try to pick apart any study that is
corporate funded, even when the study is conducted by a university and
is published in a respected scientific journal
https://vbn.aau.dk/ws/portalfiles/portal/274548813/Safety_effects_of_permanent_running_lights_for_bic ycles.pdf.

Recognize that there aren't governments all over the world funding
double-blind studies on daytime bicycle lights. You have the Odense
study funded by Reelight and conducted by Aalborg University in Denmark,
and the Trek funded study conducted by Clemson. The studies are cited by
the companies that funded them in an effort to sell their daytime light
products.

Besides these two studies, you have copious amounts of evidence on
motorcycle DRLs which logically extend to bicycle DRLs in many respects.
You also have the conspicuity studies unrelated to any type of vehicle
that just measure conspicuity between light on no light.

For those that oppose DRLs on bicycles (or cars, or motorcycles) on
philosophical grounds, no quantity of studies will change their
mind--there will always be something that they will point to in the
study that isn't perfect and declare the study to be completely invalid.
Sadly, that's the state of science in the U.S. today, and why we still
have anti-vaxers, climate change deniers, and flat-earth believers.
However in this case, it's a little more puzzling than in those other
cases because there's no downside to DRLs at all.