Just thinking about this. When I ride a scooter on main roads , which is rarely, I am very conscious that i am travelling slower ( say 80 kph) than the the other vehicle traffic. I keep a very close eye on my mirrors to be aware of who is coming up behind.
How many cyclists, who will be travelling much slower than me, have rear view mirrors and use them?
Most of the danger on Thai roads is the amount of vehicles travelling at different speeds. This is not a problem unique to Thailand but is one that has mostly been legislated out on "western" road systems.