Use this free online PHF Calculator to quickly compute the Peak Hour Factor using your traffic volume counts. PHF helps traffic engineers assess flow consistency and peak congestion within the busiest hour. Ideal for Traffic Impact Studies and signal timing design in Pakistan and worldwide.
Peak Hour Factor (PHF) Calculator
Enter 15-minute traffic volumes below to compute the Peak Hour Factor.
Interpretation Guide
| PHF Range | Interpretation |
|---|---|
| 0.70 – 0.79 | High peaking (unstable flow) |
| 0.80 – 0.89 | Moderate peaking |
| 0.90 – 1.00 | Uniform flow (ideal) |
What is Peak Hour Factor (PHF) and Why Does it Matter?
The Peak Hour Factor (PHF) is a critical metric in traffic engineering that helps evaluate how concentrated traffic demand is during the busiest hour of the day. A lower PHF indicates sharp traffic peaks—often pointing to congestion or intersection performance issues—while a higher PHF reflects more uniform and stable flow. This makes PHF particularly valuable in signal timing, intersection design, and capacity analysis.
Transportation planners and engineers frequently use PHF when preparing Traffic Impact Assessments (TIAs). You can learn more about TIA requirements and methodology in our complete guide to Traffic Impact Assessments, or download our ready-made TIA report template to streamline your submission.
If you're working on a TIA or feasibility study, don’t forget to explore our other free online tools like the Trip Generation Estimator, Trip Distribution Tool, Signal Warrant Calculator, and Catchment Area Map Tool. All our tools are designed to support transportation planning professionals, students, and consultants working across Pakistan and beyond.
For tailored assistance, check out our Transportation Planning and Engineering Design services, or contact our team to discuss your project.