This topic comes up frequently at a place that I hang out at a couple of times a week. Since most of the people that come there arrive by scooter we often see people that pull up without a helmet on. One good thing about this pub is that we are the kind of people that will reprimand our friends for this irresponsible behavior. It is well-known that Thailand is an extremely dangerous place as far as the roads are concerned and I can't imagine any good reason for not wanting to protect your head.
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I haven't been everywhere in this country but one thing I have noticed is that here in Chiang Mai the helmet law, which is a nationwide thing, is enforced a great deal more than other places that I have been. Out here in the suburbs where I live though, they are much more lax than they are in the city center. Law or no law though, I just don't understand why people would choose to not wear this very inexpensive and life-saving piece of equipment. Virtually everyone I know has had at least a minor accident on a bike and one of the people I have met since I lived here is now dead because of a motorbike accident that wasn't even his fault. He, of course, was not wearing a helmet and died from head injuries.
The way I look at it, your head is like an egg compared to the rest of your body and it cannot withstand a great deal of punishment whereas while it will suck if you suffer tons of injury to really any other part of your body, you are likely going to survive.
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There are so many instances of fatalities on scooters in this country and in a lot of them, such as the picture above from Phuket, the person even had a helmet with them but still wasn't wearing it. I see this all the time especially with scooters that have a basket on the front. The person carries the helmet with them and will put it on ONLY at areas that are known to have police checkpoints. Once through the checkpoint, they immediately take the helmet off.
Another thing that baffles me is that according to what I have heard about other parts of Thailand but not Chiang Mai is that only the driver of the bike is required to have a helmet on. What sense does that make? Is the driver the only one that is going to get injured in a crash? Of course not! I regularly see parents driving their own children with no helmets on anyone. I think about the extreme lengths that my own parents went to in order to prevent me from getting hurt and this just seems like terrible parenting.
I don't mean to sound xenophobic or anything like that, but I would expect the foreigners who mostly come from countries with very strict helmet laws to behave a bit more sensibly than the locals.
For me, I don't need a law in order to feel compelled to wear a helmet, I just do it because I enjoy not being dead or having brain damage.
For all of you people out there in other parts of South East Asia, does your scooter riding population tend to not wear helmets also? To me it just seems like madness to not do so when it is just so easy. Most of the bikes have special compartments under the seat that are specifically designed to house a helmet so no one can steal it easily.