Abstract: Installing traffic signals today involves a very complex, time-consuming, and expensive process. Signals have always had the primary purpose of getting people safely through an intersection, whether on horse or foot, riding a bicycle, or driving a vehicle. Sustainable traffic signal policies and directives are requirements an agency may have in place to ensure all traffic signals installed are safe, energy efficient, and accessible to all potential users. These documents can take the form of general plans, master transportation plans, bicycle and pedestrian plans, accessibility guidelines, directives, and signal timing and phasing policies. Traffic signals are generally the responsibility of public agencies, and before one is considered for installation, it must meet the policy requirements and follow the necessary planning procedures established by that agency. Most transportation professionals can agree traffic signals are not the solution to all traffic control problems. Alternatives to signalized intersections include education, the installation of roundabouts, and other initiatives.
You can find the article on ResearchGate: Sustainable Traffic Signal Development