An approach was developed to estimate the trendsof economic loss and construct an indicator in relationto the base year 1985 of road accidents, and analyzethe related factors to the number of deaths from roadaccidents. This study consists of two main parts. Thefirst part is the trends of economic loss and costindicator of road accidents. The second part deals withthe related factors to the number of deaths from roadaccidents in Thailand. The results of the study displays that the trendsof economic loss and cost indicator in relation to thebase year 1985 of road accidents increase every year.The positively related factors to the number of deathsfrom road accidents are alcohol consumption, economicgrowth of the services sector and the increasing numberof bus registration. The negatively related factors arethe road transportation budgets for direct and indirectroad safety, and the speed limits legislation. Theseresults have important policy implication.