WaySync-M, which is short for WaySync-Mobile, is the first of its kind and the only mobile tool currently available in the world for real-time diagnosis and evaluation of traffic signal timing plans using mobile devices. Together with its advanced features of geo-referencing and dynamic time-space diagram, it allows users to easily diagnose common issues with actuated coordinated signals, such as phase early return, transition, clock drifting, and erroneous offset inputs.