, Associate Professor, Civil, Environmental and Geo-Engineering
Ying Song, Associate Professor, Geography
Yiling Zhang, Assistant Professor, Industrial and Systems Engineering
The advent of automotive technology, such as vehicle automation and electrification, is transforming our transportation systems. While electric passenger vehicles have found their way to the market, larger vehicles such as buses and trucks are still in the early stages of adoption. At the same time, environmental issues due to greenhouse gas (GHG) emissions necessitate cleaner energy sources to replace fossil fuels. California has mandated the electrification of all transit systems by 2040, and many transit agencies in the country began pilot testing of battery-electric buses (BEBs). Primary challenges in adopting BEBs for transit service are: 1) planning for incremental transition to electric fleets and infrastructures, and 2) developing charging strategies to deal with the operational limitations of BEBs under uncertain conditions. This project aimed to develop a practical and realistic plan to utilize existing charging infrastructures and the current transit network layout to facilitate the transition to an electric transit system through an incremental deployment plan. Researchers used GIS to collect and manage spatial data from various sources, visualize route characteristics and existing charging facilities, and perform spatial-temporal analysis to identify candidate transit routes for electrification. Researchers then developed multi-stage stochastic programming models to select the routes that, by electrification, provide the highest net benefits to the environment and society. A comprehensive set of benefits (for operators, users and, society), costs (capital and operating), and operational constraints (frequent charging needs, uncertain energy consumption, etc.) were considered. The model will produce long-term infrastructure and fleet replacement plans, such as routes for electrification and charging stations to be used, and strategies for short-term decisions, such as bus scheduling or dispatching, compatible with the long-term plans.