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Traffic Signal Timing Calculator

Civil Engineering Application & Design Resources

Traffic Signal Timing Calculator

Signal timing is a collection of parameters and logic designed to allocate the right-of-way at a signalized intersection.

Preview: Traffic Signal Timing Calculator

y = t + v 2 a ± 64.4 G

Eq. 2
r = W + l v

Eq. 3
G p = 3.2 + L S p + 0.27 N p e d


t = driver reaction time (sec)
v = vehicle approach speed (ft/sec)
W = width of intersection, curb-to-curb (ft)
l = length of vehicle (ft)
y = length of yellow interval to nearest 0.1 sec (sec)
r = length of red clearance interval to nearest 0.1 sec (sec)
Gp = minimum green time for pedestrians (sec)
L = crosswalk length (ft) Sp = pedestrian speed (ft/sec), default 3.5 ft/sec
Nped= number of pedestrian in interval a = deceleration rate (ft/sec2)
± G = percent grade divided by 100 (uphill grade "+")

U.S. Department of Transportation
Federal Highway Administration