Work out intersection delay instantly with clear inputs, formula shown and shareable results.
Signal delay has two parts. Uniform delay assumes vehicles arrive evenly and depends on the green to cycle ratio; incremental delay accounts for random arrivals and oversaturation and grows sharply as the degree of saturation approaches one. Level of service at signals is graded on average control delay, with A at ten seconds and F beyond eighty.
Uniform delay
d1 = 0.5 C (1 - g/C)² / (1 - (g/C) x)
Degree of saturation
x = arrival flow / (saturation flow x g/C)
d1 = 0.5 C (1 - g/C)² / (1 - (g/C) x). Signal delay has two parts.
Because randomness matters. Even when average demand equals capacity, some cycles receive more arrivals than can discharge, and the residual queue carries forward and compounds.
This calculator takes 4 inputs: Cycle length, Effective green for the movement, Arrival flow, Saturation flow. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.