This report presents an overview of an evaluation of on-road fuel cell electric vehicles (FCEVs) by the National Renewable Energy Laboratory (NREL). The project addressed the need for current, on-road FCEV data and sought to validate improved performance and longer durability from comprehensive sets of early FCEVs, including early market vehicles. This report provides an overview of the evaluation project and partners, describes NREL's evaluation approach, and presents a summary of the results. Detailed results for durability, fuel economy, deployment and driving behavior, and specifications are published in separate reports.