Final answer:
The term 'stale' refers to a green traffic light that has been on for a while and is expected to turn yellow soon as part of its normal sequence to manage traffic flow.
Step-by-step explanation:
A traffic light that has been green for some time is considered 'stale,' and it is likely to turn yellow soon, as part of its normal sequence before turning red. Traffic lights typically follow a predictable pattern: green, yellow, then red. If a light has been green for an extended period, it suggests that the phase is about to change, as traffic lights are programmed to cycle through these colors to manage traffic flow safely and efficiently. The term 'stale green light' is a colloquial expression indicating that the green phase has been active for a while and will transition shortly.