Simulation Analysis of the Distance Between Tunnels at the Bridge-Tunnel Junction of Mountainous Expressway on Driving Safety Under Crosswinds

To analyze the influence of distance between tunnels at bridge-tunnel junction in mountainous area on driving safety under crosswind, a vehicle dynamics model is established by Carsim software. Under conditions different speeds (60km/h, 80km/h and 100km/h), wind scales (level 6–9) three alignment combinations (tunnel-straight road-tunnel, tunnel-curving tunnel-the combination straight curves road-tunnel), vehicle’s lateral offset force coefficient are used as evaluation indexes to study safety. When small, increase firstly then decrease increases. But changes not synchronized, peak value occurs earlier than offset. Finally, minimum spacing each condition speed limits for distances proposed. straight-tunnel, 20m cannot ensure when scale reaches level 9, road should be closed. curve straights curves, maintained 8 However, 6 or 7, can adopted The results suggest that vehicles’ effectively reduced reducing increasing tunnels, so risk accidents caused crosswind reduced.