Researcher also has free (speech and beer) schematics for making your own sensor and replicating the experiment.

Have you heard of this concept? Does it ring true for you? Do you live somewhere where cars pass you dangerously?

Wear a helmet or don’t, but either way, society is responsible for making bicycling safer, and encouraging more people to take a bicycle over a car trip. Mandatory helmet laws reduce the number of people cycling, and the safety in numbers factor.