What is a common issue encountered in older traffic signal systems?

A common issue encountered in older traffic signal systems is the difficulty in finding replacement components. Many older systems were built using specific parts that are no longer manufactured or widely available. As technology advances, manufacturers phase out older components in favor of newer designs, making it challenging for maintenance crews to source the necessary parts for repairs or upgrades. This can lead to increased downtime for traffic signals, impacting traffic flow and safety.

In contrast, options related to over-reliance on modern technology and increased energy efficiency are typically associated with newer systems rather than older ones. Compatibility with newer vehicles is generally not a significant concern with older signal systems, as they were designed to accommodate the vehicles of their time. Therefore, the primary issue revolves around the availability of components for repair and maintenance of aging traffic signal infrastructure.