It's required in New York as well, but I can't imagine that is seriously deterring people from riding bikes.
I've tried to explain why below, but the real point is just "from personal experience I can't image it isn't detering people from riding bikes".
The main reason a helmet is such a problem is just convenience. A bike, like a car, I can just lock up wherever I go. The helmet I would have to carry around with me all day. That makes whole day just slightly more inconvenient, and it's honestly just not worth it to me.
The second is that wearing a helmet makes me feel substantially less safe. There are two direct reasons that I can articulate for this, but I'm not sure they fully explain the effect. There are also statistics that support me, showing that wearing a helmet is correlated with a increase in collisions.
The first reason is wearing a helmet substantialy impedes my hearing. This is probably a bit foreign to people who are use to driving, but hearing is incredibly useful for knowing when a car/truck/bus/etc is coming up behind me. A helmet increases wind noises to the point where the signal is much less useful, I'm not confident I will always hear a car in time to react with one on, and I'm worse at pinpointing the location. Incidentally I find the lack of sound when driving fairly disturbing and scary, since I'm so used to being able to use it.
The second is that the extra weight on my head seems to make looking around take more psychological effort, so I end up doing it best, so I end up having less awarness of cars around me. This is a rather surprising (to me) effect, but I'm certain it's real. Of course it's not the end of the world because I do still make substantial effort to look around, it's just epsilon less often which makes me epsilon less safe.
Edit - I’m not saying I support laws enforcing helmets for adults; I just don’t think that helmet theft is a big concern.
I've had the ultra-cheap lights on my bike stolen. I've seen plenty of other bikes stripped of everything except the frame itself.
This is why I always take my helmet (and my lights) with me, lock my bike and the front wheel with a good lock, and chain lock my seat down for good measure. Haven't had anything stolen since -- even in some sketchy areas.
London, famous for rampant bike theft, and I've never had a locked up helmet stolen. Lights, I take with me; I'm not mad.
And even if the actual rate of crime is lower than the perception, it's still an anxiety people have to add to their daily routine.
Unrelated anecdote: the first time I went out with a helmet was the first time I banged my head, I ducked under a branch as I normally would, only I'd not allowed the extra room, banged my head hard and came off my bike (gently). I still wear and encourage helmet use.
- Rain (possibly solvable with a bag of some sort, but this becomes increasingly complex, consider locking).
- Locked bikes are annoyingly often bashed slightly. My bike can take the abuse, but a bashed up helmet becomes even more useless, sometimes without even showing it.
- Makes locking the bike substantially harder. If I don't want my helmet stolen I'd have to lock it through the actual helmet and not the straps. That would be a pain in the ass with a ulock (and other lock types are considered even less secure for the bike).
It's not total hearing loss, but it catches the wind which makes noise once you're going a reasonable speed. Similar to the noise you experience if you orient your head the wrong way when there is a reasonable amount of wind going by you, but you can't get rid of it by turning your head. I also find I'm much worse at pinpointing direction all the time with it on (presumably because of sound bouncing off of it... since ear's generally pinpoints sound via echo).
I've found other people who agree with me on this, and other people who don't notice it. My best guess is that the people who don't notice it just never learnt to use sound as such an important queue while biking, particularly with respect to direction, but I don't know.
“My question is, you are covered from head to toe in protective padding. So why don’t you wear a helmet?”
“The suit’s got a cervical airbag that blows up when you fall off the board, so you can bounce on your head. Besides, helmets feel weird. They say it doesn’t affect your hearing, but it does.”
“You use your hearing quite a bit in your line of work?”
“Definitely, yeah.”
Uncle Enzo is nodding. “That’s what I suspected. We felt the same way, the boys in my unit in Vietnam.”
[…]
“Our job was to go through the jungle making trouble for some slippery gentlemen carrying guns bigger than they were. Stealthy guys. And we depended on our hearing, too—just like you do. And you know what? We never wore helmets.”
“Same reason?”
“Exactly. Even though they didn’t cover the ears, really, they did something to your sense of hearing. I still think I owe my life to going bareheaded.”
put your coat on
check you have your phone and keys
Pick up your briefcase/backpack
before you leave for work?
Part of effect is that helmet campaigns paint cycling as much more dangerous as it really is. So, more risk averse people are putt off bikes entirely and less likely to use them. It makes people associate bike with picture of accident instead of pleasure.
Part of effect is that kids cant use bikes on playground "normally" how they would without helmet - they cant chase, hop on bike, go 10 meters and hop down.
Part of effect is that you cant use bike as transport device when you need your hair to look reasonably good afterwards.
Part of effect is that helmet is one more thing you have to carry with you and it might make difference between "yeah kiddo take it" and "nah, it stays home".
As a teenager I never even bothered to get a helmet because I would have to ask parents to spend money on it, and it would be inconvenient to carry around all the time. It interfered with the flexibility and fun of a bike. If I were forced to use it (and God forbid, elbow and knee protectors), it'd probably cut my bike usage in half, because what was just a matter of hopping on and riding away would become a whole dress-up game.
Related, I've seen this concept called "trivial inconveniences", and I like this essay on the topic: https://www.lesswrong.com/posts/reitXJgJXFzKpdKyd/beware-tri....
I'm a cyclist. I race mountain bikes, used to race on pavement, and still avidly train several days/week on local roads and bike paths.
I wear a helmet when I'm training or traveling a long distance at speed. On roads with cars, higher speeds = higher risk for major accident.
I don't wear a helmet when I'm cruising to the pub for a drink. Yeah, I can still fall. But, I'm on the mountain bike (relatively easy to hop off, compared to a road race bike), at slower speeds, and generally not on roads with cars.
I do wonder if part of the problem is the type of bikes popular in some counties. The US has a large number of road race bikes relative to townie/dutch-style bikes. The townie/dutch bike is slower, lower to the ground, has a step through, and more upright seated position (better visibility). All should lead to fewer major accidents.
The popularity of the iPhone and the willingness of people to give their data to data collecting entities that provide convenient services is a testament to that.