Signal Timing Designer

Enter each phase's critical lane-group flow q and its saturation flow s. The app finds the flow ratios, Webster's optimum cycle, the green split, and each approach's capacity, degree of saturation and average delay — with a timing diagram of the cycle.

⭐ Free to design · Balance … EP

① Phases

Number of signal phases

For each phase enter the critical lane-group hourly flow q and its saturation flow s (veh/h of green). The critical movement is the one with the largest q/s in that phase.

q₁ — flow (veh/h)

s₁ — saturation (veh/h)

q₂ — flow (veh/h)

s₂ — saturation (veh/h)

② Lost time & clearance

Lost time per phase ℓ (s)

Amber + all-red per phase (s) opt.

Use this cycle length instead (s) — optional

Total lost time L = ℓ × (number of phases). Give the amber to also get each phase's actual green G = g + ℓ − amber. A custom cycle uses your value for the green split.

🚦 Signal timing

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Webster fixed-time design

Sum of flow ratios Y

—

Total lost time L

—

Optimum cycle C₀

—

Design cycle C

—

Total effective green

—

Phases

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Per-phase timing

Phase	q	s	y=q/s	Eff. green g (s)	Green G (s)	Cap c (veh/h)	x=v/c	Delay d (s/veh)

Signal Timing Designer

① Phases

② Lost time & clearance

🚦 Signal timing

Per-phase timing

Worked solution