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Roadside sensors, such as camera and millimeter-wave (MMW) radar, provide traffic information beyond the visual range of intelligent vehicles in cooperative vehicle-infrastructure systems. Unlike onboard equipment, roadside sensors are affiliated with different systems and lack synchronization in both space and time. In this paper, we propose a novel spatio-temporal synchronization method of asynchronous roadside MMW radar–camera for sensor fusion, which utilizes features of the scenario to extract lane line corner points to pre-calibrate the camera. Based on the consistent time flow rate of the separate sensors, multiple virtual detection lines are set up to match the time headway of successive vehicles and conduct objective matching to track data. Finally, a synchronization optimization model is formulated and a constrained nonlinear minimization solver is applied to tune the parameters. Measure data from Donghai Bridge in Shanghai is applied to verify the feasibility and effectiveness of the method. The results determine that there are 33 frames (33*40 ms) of temporal deviation between the camera and the radar in this case. After the synchronization, the average spatial deviation is reduced from 2.47 m to 0.42 m in the X-direction and 64.06 m to 2.34 m in the Y-direction, respectively. This study provides an economical and effective way to solve the problem of spatio-temporal synchronization of roadside sensors. [ABSTRACT FROM AUTHOR]

This paper develops a new approach for tram prioritization integrating an offline traffic signal timing planner with an online tram progression controller. The offline planner optimizes tram progressions by resynchronizing traffic signals to minimize tram running times, taking into account the effect of the resynchronization on other vehicles. The online controller aims at enhancing tram reliability by adopting three control strategies—green extension, vehicle holding, and speed guidance—to instruct the trams to travel within appropriate progressions. The real-world case studies are presented to demonstrate that, comparing with the state-of-the-practice approach, the proposed approach has the potential to improve the service quality by shortening tram running time and passenger waiting time, and to mitigate the negative impact on other vehicles by avoiding triggering unnecessary green extensions. [ABSTRACT FROM AUTHOR]