Most public transportation investment and operation decisions are made by considering the benefits, costs and impacts of proposed actions, via processes that may be formal or informal. This chapter shows how public transport agencies around the world have successfully evaluated public transport plans, policies and programs. They span bus, light rail, BRT and heavy rail lines and systems. They also include capital investment, operations, pricing and other implementation policies. The discussion covers both forward and backward looking evaluations. “Ex post” (backward-looking) evaluation measures impacts of existing projects and services, which makes it possible to optimize current efforts and learn lessons for future designs. “Ex ante” (forward-looking) evaluation calculates the expected impacts of proposed projects and services, which makes it possible to select the most efficient and effective choices among available decision options.
For public transportation, evaluation is particularly important and complex because public transportation is a service operated for the public as well as an infrastructure investment. Several different kinds of measurement and modeling methods can be applied to evaluate public transportation projects and programs, depending on the context. They range from benefit cost analysis to economic and social impact studies, and their applications encompass the effectiveness of public transportation schemes in addressing transportation performance goals or to assess achievement of broader financial, efficiency, equity, environment and economic development goals. This chapter provides a framework for public transportation planners and operators to identify evaluation needs and approaches for addressing them.