Assessing the feasibility of using hardware-in-the-loop real time simulation in the signal timing design process

This dissertation covers the development and testing of a modeling environment in which traffic control plans can be designed, tested, and refined using real traffic signal control equipment. This environment is known as hardware-in-the-loop simulation or HILS. A new device, known as a controller interface device or CID, and the software to run this device, was developed as part of this research.; Four problems guided this research: (1) Can a system be designed that provides a real time link between a microscopic stochastic traffic simulation model and traffic signal controller that addresses the problems that exist with the first generation CID? (2) Can such a system provide true real time simulation with minimal or no latencies that would adversely affect the simulation results? (3) Do the results produced by real time HILS compare favorably with results produced by a software-only simulation model? (4) Do the results produced by real time HILS differ with results produced by software-only simulation for those controller settings that cannot be modeled directly or only approximately by software-only simulation?; The new CID was designed and tested and, as part of HILS, was found to meet all design objectives established for it. A detailed study of all hardware, firmware, and software latencies was conducted and showed that while latencies exist, they are not significant and do not adversely affect HILS. A set of experiments showed that the results produced by HILS was no different than the results produced by a standard microscopic simulation model for fixed time traffic control systems, thus validating the performance of the CID. However, for actuated controllers, some differences in the operation of real and simulated controllers was found. These differences show the value of using HILS for classes of problems in which transportation engineers must understand and include the effects of traffic controllers.