High visibility law yields no improvement in safety

On 3/31/2018 12:00 PM, Jeff Liebermann wrote:

The fallacy also works for the absence of evidence. (Absence of
evidence is not evidence of absence). An unchanged accident rate
after the introduction of mandatory reflective clothing does not mean
that reflective clothing does NOT have an effect on accident rate.
There could easily be a counter balancing effect. For example, it
might be that riders tend to ride more aggressively when wearing a
reflective vest on the assumption that the vest would protect them
from harm. At the same time, vehicle drivers would more easily notice
bicyclists. The two effects cancel each other resulting in an
unchanged accident rate.

In the cycling community, there are many who believe absence of evidence
is trumped by an anecdote or two - as in "I _know_ that people no longer
pull out in front of me when I wear my lucky fluorescent socks!"

Whatever the magic talisman, users deem it every bit as effective as
medieval indulgences. Anyone who doubts is a heretic to be shouted down.


--
- Frank Krygowski