Signal Timing & Intersections

Worked: a two-phase signal

A 45 mph level approach (66 ft/s): y = 1.0 + 66/20 = 4.3 s. Clearing a 60 ft intersection with a 20 ft vehicle: r = 80/66 = 1.2 s.

Critical flow ratios are 0.30 and 0.25 with 8 s lost per cycle: C₀ = (12 + 5)/(1 − 0.55) = 37.8 s, rounded up to 40 s. The 32 s of effective green splits 0.30/0.55 × 32 = 17.5 s and 14.5 s.