ITE Traffic Bowl Fundamentals and Engineering Practice Test

Saturation flow rate is the theoretical maximum number of vehicles that can pass a point in one hour when the signal stays green for the entire interval. It represents the fastest achievable release of vehicles per lane under ideal conditions, essentially the platoon clearing rate as soon as each vehicle arrives. This concept is used to estimate signal capacity and to size cycle lengths, since it sets the upper limit on how many vehicles can move during green. In practice, the actual flow during green is often lower due to start-up losses, yellow intervals, pedestrian movements, and variations in driver behavior. The other terms differ: occupancy is how much of the time a lane or detector is occupied by vehicles, a phase is a distinct stage in the signal cycle, and traffic calming refers to measures that slow traffic through a area.