Model and Approach of Solid Line Setting Based on Merge Safety and Merge Probability

Abstract

To improve the safety of merging vehicles and reduce the possibility of accidents, the easiest and most effective way is to adjust the existing traffic facilities. This study examines the requirements and approach of setting a new merge marking. First, a marking calculation model for the acceleration lane was constructed by taking the vehicle-merging probability as the limiting condition and combining the acceptable gap theory. Second, considering the limitation of ramp speed and acceleration lane length, the length of the solid merge line under different volumes and speeds was determined, and the value under different cases was given. Third, the safe change clearance and the length of the solid merge line under different scenarios were analyzed with numerical simulations using MATLAB. Finally, VISSIM was used for the simulation verification of the actual merging zone. The calculation results are that at the same probability, the increase of the volume outside the mainline, the longer the length of the solid merge line. When the volume of the outer lane is 100 pcu/h and 500 pcu/h, the actual gap value is greater than the minimum gap value, and vehicles can safely merge into the mainline. When the volume is 1000 pcu/h, the gap value is less than the minimum safe gap and cannot meet the safe merging, and control measures need to be taken for the lane. The results of the TTC conflict analysis show that it is recommended to set the solid merge line at service level two and above and that the service level three can be set in some cases. The setting of the solid merge line can further increase the vehicle acceleration space, improve the merge speed, and enhance the safety of the merge.