Electric vehicles, as an emerging transportation platform, have been introduced over the past several decades due to various concerns about air pollution and the contribution of emissions to global climate change. Although electric cars and buses have been the focus of much of electric vehicle development, smaller low-speed electric vehicles are used extensively for transportation and utility purposes in many countries. In order to explore the viability of fuel cell - battery hybrid electric vehicles, empirical fuel cell system data has been incorporated into the NREL's vehicle design and simulation tool, ADVISOR (ADvanced Vehicle SimulatOR), to predict the performance of a low-speed, fuel cell - battery electric vehicle through MATLAB Simulink. The empirical fuel cell system data are obtained through systematic tests of a 1.2 kW Proton Exchange Membrane (PEM) fuel cell stack that is used as the power plant for a fuel cell - battery hybrid electric scooter. The modelling and simulation of the fuel cell electric scooter using new performance modules built using ADVISOR provide valuable feedback to the design, and a platform for the design optimization of the fuel cell power system. Various optimization methods, including a sampling based optimization algorithm, were used to explore the viability and options of a low cost design for urban use. This study serves as the foundation for further research on the modeling and design optimization of PEM fuel cell power system, and fuel cell powered, low speed electric vehicles.