Institute of Transportation, MOTC

       With the rising awareness of global environmental protection, the transportation department puts forward relevant policies and hopes to promote green transportation to achieve the target of greenhouse gas reduction. The purpose of this research is to study the issue of electrification of the existing fleet. From the perspective of the operator, under the goal of minimizing the cost of the fleet, the existing fleet needs to be replaced gradually because of considering the operating costs, the supply limitation, routing problem, other operational aspects, and the time pressure of the policy of replacing current buses by electric buses. The operator needs the plan for the replacement schedule of electric buses.
        This study proposes a mathematical model of the twice replacement method of current buses, and introduces the concept of the target year and the supply limitation. Then, we put the simulation data to solve it, and finally conduct sensitivity analysis to discuss the impact of different factors on the replacement result. The results show that the combination of vehicle replacement years is related to the pressure of the target year, the age of vehicle retired, and the limitation of supply. The results also reveal that the price of electric buses is an important factor affecting the replacement schedule of electric buses. Using the model, we can get the result of the replacement of the diesel buses before the target year for the operator as a reference.