Factors Associated with Motorcylists' Safety at Access Points along Primary Roads in Malaysia

Abstract: More than 50% of road accident fatality victims in Malaysia are motorcyclists, numbering more than 4,000 fatalities per year. The aim of this thesis is to investigate motorcyclists’ road safety problems in general in Malaysia, and narrow down the focus to the most salient road infrastructure related risk factors. After identifying access points on primary roads as hazardous sites, observations of road user behavior at these sites have been carried out in order to establish behavioral and design factors associated with a hazardous outcome of interaction between motorcyclists and other road users. The data collected for this thesis ranges from accident records to on-site observational data including speed and behavior. The method ranges from cross-sectional analysis of accident data to advanced statistical modeling. The thesis finds that Malaysian road accident statistics suffer from disproportional underreporting of severe injuries. A motorcycle Safety Performance Function estimates that an increase in motorcycle fatal accidents per kilometer is highly associated with an increase of access points per kilometer and the average traffic volume of motorcycles. The observational study has detected a hazardous right turning movement, i.e. the Opposite Indirect Right Turn, which is performed by 18% to 26% of right turning motorcyclists entering a primary road from an access point. Moreover, motorcyclists entering the primary road are involved in serious traffic conflicts to the same extent as other vehicles. The advanced statistical analysis shows that the outcome for motorcyclists involved in a serious traffic conflict is influenced by their manner of entry into the primary road from the access point, their stopping behavior and the lane width of the primary road. Overall, this thesis shows the importance of identifying motorcyclists’ behavior, as well as road environment attributes, in order to understand the road safety situation of motorcyclists.