  The freeway on-ramp merging section is often identified as a crash-prone spot
due to the high frequency of traffic conflicts. Very few traffic conflict
analysis studies comprehensively consider different vehicle types at freeway
merging section. Thus, the main objective of this study is to analyse conflicts
between different vehicle types at freeway merging section. Field data are
collected by Unmanned Aerial Vehicle (UAV) at merging areas in Shanghai, China.
Vehicle extraction method is utilized to obtain vehicle trajectories.
Time-to-collision (TTC) is utilized as the surrogate safety measure. TTC of
car-car conflicts are the smallest while TTC of truck-truck conflicts are the
largest. Traffic conflicts frequently occur at on-ramp and acceleration lane.
Results show the spatial distribution of lane-change conflicts is significantly
different between different vehicle types, suggesting that vehicle drivers
should maintain safe distance especially car drivers. Besides, in order to
decrease lane-change conflict at merging area, traffic management agencies are
suggested to change dotted lie to solid lane at the beginning of acceleration
lane.
