Thailand, one of the ASEAN countries is located in the Main land of Asia. The population is 63.07 million inhabitants with the number of car 26.076 million, this figure has increased rapidly from 12.579 in the year 1994 up to 26.07 in the year 2003. According to the Government policy and the location, Thailand makes a target of being Land Transport and Aviation hub in Southeast Asia and South China Region. That will enable land transport in Thailand grow up rapidly. However the problem of Road safety may occur, accordingly. Road Safety is one of the major issues for Thailand. We lost more than 100,000 million baht in the year 2002, with the number of death 13,116, serious injuries 190,322 and minor injures 1,338,712. The cost of road accident is nearly 2.1% of total Gross Domestic Product (GDP) for Thailand. With this record, Thailand's road fatalities are the highest among the other 9 ASEAN countries. From our study, there are three major courses of problem, which are people, vehicle, road and road environment. We also find out that five major causes which make road serious accident on road in Thailand, are motorcycle crash, drunk drive, speeding, the New Year and Songkran festivals and also road safety culture initiation.