The bi-level optimal model of ramp type selection of relative interchanges on consideration of regional traffic affection

Traditionally, the type of ramps of interchange in urban road network was determined singularly. But in fact, there are many factors from the regional road network which can influence the selection decision-making, and on the other hand, the selection result influences the whole regional network operational efficiency not just the single interchange itself. So in this paper, a bi-level optimal model of ramp type selection of relative interchanges is built, on the consideration of ramp traffic capability, ramp features, road network influence factors i.e. the upper model with an aim to minimize the total integrated costs including the relative network resistance, the lower model with an aim to reach an user equilibrium on relative road network traffic flow. At last a genetic algorithm is advised to solve the bi-level model mentioned above.