Did that article in the Post make you mad enough to take off Tuesday afternoon and testify in Annapolis? Hopefully so, if you live in Maryland. But either way, if you have a little time to do some reading, you could still help. Alot.
I think we need a simple, believable estimate for the number of people who stop biking because of a helmet law, based on the literature. The problem is, we can't realistically assume that 30-40% of people will stop biking just because that happenned in a particular state in Australia during the 1990s. Nor can we assume that no one will stop biking, just because the law had a minimal impact on the cycling population of Bremerton, Washington.
I think our best bet is to look at the ratio of the increase in helmets to the decrease in cycling. If the law has few teeth, both the numerator and denominator will be low; if the law imposed serious penalties on a population where no one had previously been using helmets, then both the numerator and the denominator should be high. But the ratio may be fairly similar, because it reflects the same decision: I don't have a helmet with me, should I ride anyway?
As an example, I started with the article by LeBlanc et al. concerning the mandatory helmet law in Nova Scotia. There is a paywall but the journal published some comments which are accessible. The comment by Tom Trotter replicates some of the data. If you calculate the number of helmeted cyclists during the first two years and the last two years, and compare that with the number of cyclists observed, you get the ratio that about 1 person stopped cycling for every 3 people who started wearing a helmet. (The middle year seems to be anamolous.)
I know that some of you have access to other articles that compare the increase in helmets with the decrease in cyclists. If you are able to read one (or more) such articles and dig through it enough to find the change in each, that would help so that we could rely on as wide of a research body as possible.
(Jim Titus is a cycling advocate from Prince Georges County. The opinions in this post do not represent the views of any organization with which he is affiliated.)