Foundation for Self-Tuning Closed-Loop Progression System (0-4729-1)

Closed-loop systems are widely implemented in Texas arterials to provide efficent operation of arterial intersections while still providing signal progression. Nevertheless, poor progression can be observed along most arterials due to outdated offsets, short-term variations in traffic pattem (early-retum-to-green), or changes in arterial's speed and changes in traffic volumes. The limited abilities of closed-loop systems to adapt to traffic variations have stimulated interest into incorporating the technologies of adaptive control systems (ACSs) into closed-loop systems in order to address such issues. These integrated-type systems require lower cost and minimal staff training, in comparison to fully adaptive systems, since traffic engineers and technicians managing the traffic signal operating systems are already familiar with the closed-loop logic. The objective of this research is to develop, implement and test an algorithm that will address the limitations of previous efforts in this area of real-time offset-tuning. This first-year report lays the foundation for the development of this algorithm. The report also documents the proposed structure for field implementation.