ABSTRACT In order to solve the problem that the interchange exit has become the black spot of highway accident due to the change of vehicle lanes and the unreasonable installation of safety facilities after the change of four lanes to eight lanes of highway. Firstly, through comprehensive analysis of vehicle operation mode, traffic flow characteristics and driver behavior characteristics, based on the characteristics of eight-lane expressway, the traffic safety facilities are designed more optimally, and a new lane-changing model is proposed to effectively guide the driver to drive safely. Secondly, it analyses and calculates the visible area and the critical condition of vehicle occlusion for signs of different supporting modes, calculates the occlusion probability under various traffic conditions with the help of VISSIM traffic simulation software, and combines the advantages of various supporting modes, the characteristics of traffic signs at different locations at the exit of eight-lane Expressway and the overseas economy. The test shows that the exit signs of the eight-lane Expressway in China should be set at the level of 3 km, 2 km, 1500 m and 800 m, as well as the exit signs and bifurcation points. Finally, through the analysis and optimization of traffic marking and anti-collision facilities at the exit, mainly including visualization optimization and guidance enhancement, the purpose of optimization is achieved through color marking and grading lane-changing marking. In view of the characteristics of highway triangular collision, the collision avoidance facilities are replaced by the latest steerable cushion, and warning signs are added. The guidance sign can enhance the driver's recognition of the exit and improve the overall safety of the exit. KEY WORDS Eight lanes, Highway exits, Traffic safety facilities, Driving characteristics, Optimal design，VISSIM simulation

CICTP