This paper presents an emergency vehicle priority control system based on connected vehicle technology, called MMITSS priority. Traditional preemption does not consider the effect of the current traffic situation, such as the presence of a freight vehicle in the dilemma zone, on an opposing movement and can have a significant negative impact on the minor movements of vehicles. A mixed integer linear programming model is developed which can consider the priority requests from multiple emergency vehicles and dilemma zone requests from freight vehicles that could be trapped in the dilemma zone. The optimization model provides an optimal schedule that minimizes the total weighted priority request delays and dilemma zone request, as well as some flexibility to adapt to other vehicles in real time. The flexible implementation of the optimal signal timing schedule is designed to improve the mobility of the non-emergency vehicles. The approach has been tested and evaluated using microscopic traffic simulation. The simulation experiments show that the proposed priority control method is able to improve the travel time of the vehicles on the minor street while ensuring safe passage of the freight vehicle at the dilemma zone without significantly delaying the emergency vehicles. The method is implemented at the Maricopa County SMARTDrive ProgramSM test bed in Anthem, Arizona.

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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.