基于CarSim仿真的雨天不同线形互通式立交匝道行车安全及速度阈值分析OA

To clarify the characteristics of ramp alignment of interchanges and the impact of rainfall on driving safety,this study takes the hub interchange project of Kunming Northwest Ring Expressway as an example.Based on four ramps with distinct alignments are selected(Ramp A and B are small-radius single-curved ramps,and Ramp C and D are S-shaped curved ramps),a coupled simulation model integrating vehicle dynamics and road environment is established by CarSim software.Lateral acceleration,yaw rate,lateral offset and steering wheel angle are chosen as core evaluation indicators to compare vehicle driving stability under different road friction coefficients.The results show that when the road friction coefficient decreases from 0.5 to 0.2,the lateral acceleration doubles if the driving speed rises by 50％than the design speed;Under heavy rainfall(μ=0.2),the safe driving speed of Ramp A and B drops by 2.5％to 12.5％than the design speed.SUV face a remarkably higher instability risk than passenger cars,requiring an additional speed reduction of 5～8 km/h.This study identifies the coupled influencing factors of lateral offset on interchange ramps on rainy days.The core safety management principles of"reducing speed to adapt to low friction coefficients and setting speed limits matching alignment curvature"is proposed,which can provide data ref-erence for the optimization of interchange ramp design and differentiated speed limit management on rainy days.