Measure delay, capacity, and green efficiency instantly. Test cycle length, demand, lanes, and saturation assumptions. Improve staging decisions with clearer traffic performance forecasts today.
The page follows a single-column layout. Inside the calculator, inputs use 3 columns on large screens, 2 on medium, and 1 on mobile.
This calculator uses a planning-level signalized intersection control delay method. It combines adjusted demand, effective green ratio, capacity, uniform delay, incremental delay, and a starting queue adjustment.
1) Adjusted flow rate
v = V / PHF
2) Effective saturation flow
s_eff = s × n × f_adj
3) Green ratio and capacity
g/C = effective green / cycle length
c = s_eff × (g/C)
4) Degree of saturation
X = v / c
5) Uniform delay component
d1 = PF × [0.5 × C × (1 - g/C)^2] / [1 - min(1, X) × g/C]
6) Incremental delay component
d2 = 900 × T × [(X - 1) + √((X - 1)^2 + (8 × k × I × X) / (c × T))]
7) Initial queue adjustment
d3 = (1800 × q0) / (c × T)
8) Total control delay
d = d1 + d2 + d3
These sample scenarios show how the calculator can be used to compare construction staging or signal timing alternatives.
| Scenario | Volume (veh/h) | PHF | Lanes | Green (sec) | Cycle (sec) | Capacity (veh/h) | Delay (sec/veh) | LOS |
|---|---|---|---|---|---|---|---|---|
| Base staging case | 850 | 0.92 | 2 | 34.00 | 90.00 | 1,363.78 | 47.25 | D |
| Longer cycle test | 850 | 0.92 | 2 | 40.00 | 110.00 | 1,312.73 | 55.65 | E |
| Higher demand peak | 1,100 | 0.90 | 2 | 34.00 | 90.00 | 1,335.07 | 82.37 | F |
Intersection delay is the average extra time drivers experience because of signal control, slowing, stopping, and queuing at an approach or lane group.
Yes. It is useful for planning-level checks during temporary traffic control, lane closures, detours, or phasing reviews. Final designs should still be checked against local standards and full traffic analysis requirements.
Peak hour factor adjusts the average hourly demand to reflect short, sharper peaks. Lower PHF values usually increase adjusted demand and raise delay estimates.
Saturation flow is the ideal discharge rate for a lane or lane group during effective green. It depends on lane width, heavy vehicles, grade, turning movement, and local conditions.
The volume-to-capacity ratio shows how hard the approach is working. Values near 1.00 indicate tight operation. Values above 1.00 suggest oversaturation and likely queue growth.
Construction zones, incidents, and earlier cycles can leave vehicles already waiting at the start of analysis. Including that queue gives a more realistic starting delay estimate.
Level of Service is a traffic performance grade based on average control delay. Lower delay gives a better grade. Higher delay pushes the approach toward LOS E or F.
No. This version is built for signalized intersection planning. Unsignalized or roundabout studies need different capacity and delay relationships.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.