Dynamic Offset Tuning Procedure Using Travel Time Data

Vehicle reidentification equipment and algorithms are approaching the point at which collection of real-time arterial link travel time data will soon be possible. Such equipment and algorithms will provide a new way for traffic control systems to automatically measure their performance and adapt in real-time to the actual traffic demands on the system. A procedure is described that uses the concept of link travel time data to set offsets off-line for a coordinated actuated arterial signal system. The offset setting procedure is developed in CORSIM and based on recording individual vehicle travel times between coordinated actuated intersections. Establishing offsets in this manner mitigates the “early return to green” problem associated with coordinated actuated systems and accounts for downstream queues that may negatively affect progression. The off-line procedure presented provides the foundation for an on-line algorithm that could adjust offsets based on real-time travel data.