Road traffic accidents induce serious social costs. Traffic safety improvement programs proposed and carried out by the government should be guided by analysis of accident casualty statistics. In addition, in order to measure and reflect the integrated safety levels of overall traffic systems, proper road safety performance indicators are needed. Road safety performance indices can be employed to measure the benefits of safety improvement expenditures. This study identifies the main road safety issues in Taiwan determined by analyzing the road crash database built by the National Police Agency. This study then constructs a measurement framework for road safety performance indicators, including fatality/injury indicators, key behavioral indicators and policy indicators. Principal Component Analysis (PCA) is used to combine correlated variables and to obtain the weights for the variables. The principal component scores are used to measure the road safety performances of counties and cities. The results show that the performance ranking of each type of road safety performance indicator varies with different comparison bases. Counties and cities can identify their specific traffic safety problems according to the different comparison results of different road safety performance indicators, and allocate funds to the proper road safety improvement projects to increase the application efficiency of their expenditures. Overall, the traffic safety performances of Taipei City, New Taipei City and Tainan City were better; and the traffic safety performances of Taitung County, Tainan County, and Taichung County were relatively worse. In addition, there were differences in the road safety performances between counties and cities located in urban or rural areas.