Abstract: A road intelligent management idea for the mixed traffic of cars and trucks in the station, port, etc. was proposed by monitoring the changes of road service level. The impact of road slopes and mix rates on road service level was analyzed by the simulation of VISSIM. The results showed that the slope change has little effect on the service level of large vehicle lane, its service level maintained above level two. The car lane’s service level is more sensitive to road slope. With the increase of road slope, the proportion of level-four service level is gradually increasing. The mix rate has little impact on the service level of large vehicle lane. When the cars mix rate on large vehicle lane reaches 40%~50%, the service level of large vehicle lane reduced from level one to level two. The mix rate has a greater impact on the service level of car lane. When trucks mix rate on car lane is about 5%~10%, the service level of the car lane reduced from level two to level three, and the road traffic efficiency degrades. In order to cope with the traffic safety hazards brought by the mixed traffic, the intelligent transportation system should release relevant information in time to divert traffic and strictly control the mix rate, especially trucks mixed into car lanes. Keywords: intelligent transportation; raod service level; mixed traffic; mix rate; road slope

CICTP