Yes, motorbikes are an important form of transportation in SE Asia.
There's a dealer/showroom in the next village, 999 baht down, ($28???) and not sure how much per month, but many end up being repo-ed.
The local farmers and non-skilled workers make $100-200 a month.
A car is still only a dream for most people in SE Asia.
The older people tend to ride them more cautiously, I guess the urge to push the envelope when you are a kid is kind of universal, for boys.
We were in a bigger city yesterday running errands, and I think the most people I saw on one motorbike was 5.
Motorbikes aren't really the problem, but mix them in with immature people driving cars, and very little traffic law enforcement, and it gets interesting.
Here in Thailand they do tend to drive the wrong way on the highway, or shoulder. It gets pretty interesting.