Review and Taxonomy of Advanced Traffic Signal Control

Research on advanced traffic signal control (ATSC) extends back to at least the 1960s, and many algorithms for ATSC have been proposed over the years. This paper provides a survey of this research, focusing on the evolution of ATSC starting from its origins; defines a vocabulary of ATSC algorithms; and proposes a taxonomy for organizing them, accompanied by a consistent vocabulary for discussing the control concepts. We begin with the concept of control strategy based on whether the algorithm uses conventional coordination patterns (cycle, offset, and splits) or real-time control. Next, we classify the ATSC methods according to their topographic structure (local-only, system/hierarchical), time resolution of decision-making (continuous versus planning-horizon), type of decision (rule-based or optimization), objective function, and additional subcategories relevant to certain families of methods. These various elements of system control are organized into a taxonomy of ATSC to help future researchers understand the wide diversity of algorithmic approaches to the signal control problem that have been proposed to date, and which can be updated or expanded to incorporate future research.