Which traffic signal coordination method is generally considered the least expensive?

Answer: B — Time-based coordination

Time-based coordination is recognized as the least expensive traffic signal coordination method due to its simplicity and ease of implementation. This method relies on pre-established signal timing plans that are based on historical traffic data and patterns, which do not require ongoing adjustments or real-time data processing. Once set, these timers can operate automatically without the need for complex hardware or continuous monitoring. This approach allows for effective traffic flow management, especially in areas with predictable traffic patterns, making it cost-efficient compared to more advanced techniques. The other methods, such as traffic adaptive coordination, traffic responsive coordination, and manual coordination, often involve higher costs due to the need for specialized equipment, continuous data input, and potentially more personnel and maintenance efforts to manage the systems effectively. This makes time-based coordination particularly attractive for municipalities and agencies looking to optimize costs while still addressing traffic flow.