Virtual Controller Interface Device for Hardware-in-the-Loop Simulation of Traffic Signals

Microscopic traffic simulation has been widely used for the design and/or evaluation of a new signal control strategy prior to field implementation. One of the most popular simulation approaches is the Hardware-in-the-Loop Simulation (HILS), which employs a Controller Interface Device (CID) to connect a physical signal controller to the simulation software to improve the accuracy of simulation. This paper documents the development and performance evaluation of a Virtual Controller Interface Device (VCID) based HILS. Different from the traditional physical CIDs, VCID provides wireless communication between signal controllers and simulation software through the National Transportation Communications for ITS Protocol (NTCIP). Controlled simulation experiments were conducted to compare the performance of VCID-based HILS with the Emulator-in-the-Loop Simulation (EILS), Software-in-the-Loop Simulation (SILS), and the traditional HILS. Queue length, delay, and vehicle trajectories were employed as performance measures. Simulation results show that VCID is an accurate and reliable tool for traffic signal simulation. In addition, since VCID-based HILS enables real-time updating of signal controller parameters during the simulation through the Simple Network Management Protocol (SNMP), it can efficiently assess the adaptive signal control algorithms that are developed based on the real-time traffic flow data collected by Connected Vehicles (CV) or Intelligent Transportation Systems (ITS).