This primer has been developed to assist agencies in establishing and monitoring a useful set of work zone safety and mobility performance measures. Work zone performance measures are metrics that help to quantify how work zones impact travelers, residents, businesses and workers. Work zone performance measures help agencies improve their understanding of how their decisions during planning, design, and construction affect work zone safety and mobility, and thus can help improve how they make decisions for future work zones. The primer describes possible work zone performance measures, and provides guidance to help agencies select and implement measures that make sense for their own work zone programs. The primer outlines the methods and technologies that are available to gather data to monitor the various possible measures and procedures for calculating specific performance measures from different types of work zone traffic monitoring data. The primer also discusses the use of measures across multiple projects to assess an agency's overall efforts and outcomes against its policies and goals.