Each year, bus accidents in Thailand account for some 2.5 percent of total traffic accidents with estimated 600-1000 deaths as against some 13,000 annual road tolls. Even though the crash figure is relatively small compared to those for car and motorcycle accidents, but, the consequence of bus crashes is often much more serious with relatively high number of fatalities and injuries as well as property damages. Factors affecting bus crashes therefore need to be first identified in order to improve safety performance of the bus transport services. This national bus accident research study explores and determines the factors affecting bus accidents in Thailand with emphasis on attitude and experience of bus drivers and bus passengers. As a controller of a bus, the driver has a major role in the safety of bus passengers and other road users. Understanding of both the driver's and passenger's characteristics and attitude on safety is thus crucial. The surveys conducted in the study cover the whole area of Thailand namely: Bangkok Metropolitan, Northern, North-eastern, and Southern regions. Four bus route categories are selected for the survey in order to differentiate among the route types. The study described in this paper is a part of the national research which among other things is to survey safety perception of four groups of stakeholders i.e. the passenger, the bus driver, the bus operator, and responsible government agency. Final results from this research are expected to be used in forming public transport safety policy for Thailand with the goal to improve safety performance of bus transport service. Comparison and integration of results from the four study areas will be reported.