your helmet definitely prevented a traumatic brain injury. full stop.
thing is, statistics say you’re more likely to catch a TBI in an automobile than from bikes, if we assume bike accidents are just a fraction of the “unintentional falls” that the data is lumped together as in this CDC report. unfortunately, I couldn’t find any (heh heh) head-to-head bike and car data, and there doesn’t seem to be any analysis I could quickly find that says how many of the auto TBIs were because of no seatbelts, which is frustrating.
given the statistics but depending on your preference, you should definitely be wearing a helmet in a car assuming you wear one on a bike; or, viewed the other way, if you’re comfortable with not wearing a helmet in a car, you’re statistically safer on a bike, ergo may as well skip it then, too.
but I think that’s the point, do what you’re comfortable with. as a kid, me and my mom never wore helmets on our fairy extensive bike rides. but when I started commuting to highschool in Nashville traffic, I always wore one because I was a noob (to commuting) and scared. in my twenties, I started phasing it out but still wore one for MTB because that was intentionally risky riding. then in my late twenties, I was a bike messenger and I wore one on the job for the same reason, but not off the job since I was chillin and the big drive time was over.
shouts out to @anon81133038 for his additional in-depth helmet info so I didn’t have to look it all up and type it out : )
