Transit Frequency and Capacity Calculator
What a bus, tram or train route delivers from its headway — capacity per hour in each direction, the average wait for a passenger who just turns up, and the vehicles needed to run it.
Capacity is vehicles per hour × the seats and standing room each carries × the load factor you plan for (80–90% at the peak).
How the transit frequency and capacity calculator works
Capacity is vehicles per hour × the seats and standing room each carries × the load factor you plan for (80–90% at the peak). A passenger arriving at random waits half the headway on average, which is why frequencies of every 10 minutes or better are what make a service “turn up and go”. The fleet needed is the round-trip time (including layover) divided by the headway, rounded up.
Formula: capacity/h = 60 ÷ headway × vehicle capacity × load factor; wait = headway ÷ 2; fleet = ceil(round trip ÷ headway)
Worked examples
| Inputs | Capacity per hour per direction | Note |
|---|---|---|
| Every 10 minutes, 70-passenger buses, 90-minute round trip | 357 passengers | 357 an hour; 9 buses |
| Trams every 6 minutes, 180 capacity | 1,530 passengers | 1,530 an hour; 20 trams |
| An hourly rural bus | 27 passengers | 27 an hour; 3 buses |
FAQFrequently asked questions
Why is the average wait half the headway?
If passengers arrive at random, they are equally likely to arrive anywhere in the interval between vehicles, so the expected wait is half of it. Above about 12-minute headways people start timing their arrival to the timetable, and the real wait falls below that.
What load factor should I plan for?
About 85% at the peak hour leaves room for bunching and uneven loading along the route; planning for 100% means the last stops see full vehicles pass. Off-peak loads are often 30–50%.
What capacities do vehicles have?
A standard 12 m bus about 70 (40 seated), an articulated bus 110–120, a tram 150–250, a suburban train 800–1,500 depending on length and standing allowance.
How does the fleet figure change with the timetable?
Halving the headway doubles the fleet for the same route. Layover at the ends (10–15% of running time) keeps the timetable recoverable and is included in the round trip.
Where these figures come from
- UN-Habitat — Urban Indicators Guidelines — density, green space and public space benchmarks
- World Health Organization — Urban green spaces — the 9 m² per person minimum
- ITE — Parking Generation Manual — parking demand rates by land use
- Office for National Statistics — Population estimates — the UK's national statistics agency
Last checked: September 2026. Default per-capita rates are mid-range figures from national statistical agencies and utility reports; every one is an input you should replace with the local figure.