The Nation, an English newspaper for Thailand, has a short item about traffic causalties today.
Estimated 50,000 people end up mentally or physically disabled after a traffic accident every year. 976,357 people were injured in accidents 2005.
The article does not say if these numbers include tourists or expats. Thailand has about 62 Million inhabitants. Put that into relation and it sounds as if there are accidents all the time.
So is Thai traffic very risky? Maybe. The article does not mention the number of accidents.
Students got to school, three kids on one motorbike, songteaws, these pick-up trucks with two benches along each side, are often packed with people and totally overloaded, whole families go to town on one motorcycle, in peak time busses are crowded.
One accident usually means there are lot of people involved even if only two vehicles crash.
The risk is certainly higher than in countries where people can afford the regular maintanance of their vehicles and government pulls unsafe transportation off the streets.
The Thai government reacted with new laws the last years. I.e. now motocycle riders have to wear helmets. If they do, once the traffic police has gone home, is a complete different story. And the foreigner here are not much better.