Evaluative assessment of adaptive traffic control systems in field and microsimulation

Vehicle miles of travel in the U.S. surpassed the 3 trillionth mark in 2006. With an increasing driving population and nearly static rate of transportation capacity building, there is an immediate need for greater efficiencies in operations. Traffic signal control systems provide the opportunity to improve intersection performance by reducing travel time delays, number of stops, and other measures. The result is better use of the existing transportation network with secondary benefits to the environment in terms of lower vehicle emissions.;Traffic signal control provides safe passage for vehicles at intersecting roadways. Beyond the fundamental safety aspect, these systems and devices attempt to maximize the flow of traffic through efficient use of signal timing plans. Conventional traffic signal control uses timing plans that anticipate the flow of traffic for numerous periods throughout the day over the course of the year. Some of the plans also utilize vehicle detectors that preemptively adjust phases according to traffic conditions. However, all conventional traffic signal control timing plans experience aging soon after they are optimized.;Adaptive traffic control systems offer an advanced algorithm-based regime for minimizing aging of signal timing plans and maximizing intersection performance. SCATS and SCOOT are two widely deployed adaptive traffic control systems that have been in development and use for over 30 years though they have not been extensively evaluated. One reason is the cost and commitment involved: in order to evaluate these systems, they must first be installed. This dissertation, which is a compilation of published works, answers the question: Is there an alternative to field evaluations of adaptive traffic control systems?;This research evaluates two well-known adaptive traffic control systems and compares their performance to conventional control. Results show that adaptive traffic control systems offer superior benefits over conventional control across all performance measures. In the field, SCATS improves overall operations in terms of travel time, stopped delay and number of stops. In microsimulation, both adaptive traffic control systems deliver improved though similar delays over conventional control. SCATS cycle lengths are more responsive while SCOOT keeps cycle lengths at lower levels for a longer time. Comparing the two evaluation methods, microsimulation is able to replicate field performances and proves to be a capable alternative to field evaluations of adaptive traffic control systems.