What is “effective green time”?

What is “effective green time”?

• A. The portion of cycle when an approach can actually discharge vehicles, after accounting for amber and lost time.
• B. The total cycle time for the entire intersection.
• C. The time during which conflicting approaches have a green phase.
• D. The time the signal is red.

Answer: (A)

Effective green time is the portion of the signal cycle when an approach can actually discharge vehicles. It isn’t the full green interval because there’s amber time during the transition and lost time from driver reaction and the moment the queue starts to clear. So you subtract the time lost to reaction and the amber interval from the green time to get the usable discharge time. The other options describe the total cycle length, the green time for conflicting movements, or red time, none of which capture the actual productive period for one approach.

Effective green time is the portion of the signal cycle when an approach can actually discharge vehicles. It isn’t the full green interval because there’s amber time during the transition and lost time from driver reaction and the moment the queue starts to clear. So you subtract the time lost to reaction and the amber interval from the green time to get the usable discharge time. The other options describe the total cycle length, the green time for conflicting movements, or red time, none of which capture the actual productive period for one approach.