Abstract:   In order to reduce the difference of risk distribution among the populated areas along hazardous materials transportation route, a vehicle scheduling method considering risk equity is proposed when hazardous materials are transported simultaneously between multi origindestination (OD)  pairs. The risk equity evaluation method which reflects the risk difference among all populated area by standard deviation  is proposed firstly. A vehicle scheduling model focusing on risk equity is designed, and the periodic scheduling scheme is obtained to reduce the differences of the accumulation risk in inter regional population so as to achieve a goal of risk equity. For reducing the solution difficulty of the model, a twophase algorithm is proposed after decomposing the model and increasing the interaction among decisionmakers. The example analysis shows that the method can get the optimal vehicle scheduling by adjusting the absolute frequency of vehicles in different routes selection, and can realize the goal of risk equity with the premise of acceptable total cost and total risk.

Key words:  highway transportation, vehicle scheduling, multiobjective optimization, hazardous materials transportation, risk equity