This paper presents a priority-based coordination system that provides preferential treatment to vehicles traveling along a coordinated route. A mixed-integer linear program model is enhanced to consider coordination as a form of priority along with the multi-modal priority for eligible emergency, transit, and freight connected vehicles and provides dilemma zone protection to freight vehicles in a connected vehicle environment. The optimization model generates an optimal signal timing schedule that minimizes the total weighted delay of the coordination requests, priority requests, and dilemma zone requests, and maximizes the flexible implementation of the optimal signal timing schedule. The optimal signal timing schedule allows real-time vehicle actuation using traditional vehicle detection. The simulation experiments and statistical analysis show that priority-based coordination can achieve performance equivalent to a traditional coordination system. The priority-based coordination method is integrated into the priority control Multi-modal Intelligent Traffic Signal System and is implemented in the Maricopa County SMARTDrive ProgramSM test bed in Anthem, Arizona, and in Portland, Oregon.