Calculator Inputs
Example Data Table
Sample values for a medium-size site shuttle between parking and workface.
| Peak demand (pph) | Capacity | Load factor | Travel RT | Dwell | Layover | Cycle | Recommended headway | Buses required |
|---|---|---|---|---|---|---|---|---|
| 240 | 30 | 90% | 18 min | 6 min | 4 min | 28 min | 6.75 min | 5 |
| 180 | 25 | 85% | 16 min | 5 min | 4 min | 25 min | 7.08 min | 4 |
| 320 | 40 | 90% | 22 min | 8 min | 5 min | 35 min | 6.75 min | 6 |
Values are illustrative. Confirm dwell times using on-site observations.
Formula Used
- Cycle time:
Cycle = Travel_roundtrip + Dwell_total + Layover - Effective capacity per trip:
C_eff = Capacity × (LoadFactor/100) - Recommended headway (minutes):
H_rec = 60 × C_eff / Demand_pph - Buses required:
N = ceil(Cycle / H_rec)(equivalentlyceil(Demand_pph × Cycle / (60 × C_eff))) - Achievable headway with a fleet:
H_fleet = Cycle / Buses_available - Fleet capacity (pph):
Max_pph = C_eff × (60 / H_fleet)
Use a lower load factor if comfort or safety is critical.
How to Use This Calculator
- Enter peak demand during shift change or break periods.
- Enter capacity and a realistic load factor for operations.
- Enter round-trip travel, total dwell, and recovery time.
- Click Calculate to get recommended headway and buses required.
- Optional: Enter buses available to check feasibility and margin.
- Optional: Enter a target headway to size buses for a goal.
- Download CSV or PDF for reporting and approvals.
Bus Headway Planning for Construction Shuttles
Construction sites often rely on shuttle buses to move crews from parking areas, muster points, or remote laydown zones to active workfaces. When headway is too long, queues build quickly, late arrivals increase safety exposure at gates, and supervisors lose productive minutes at shift change. When headway is too short, buses run underutilized and operating cost rises without measurable benefit. This calculator helps balance both by linking passenger demand to effective bus capacity and full cycle time.
Start by estimating peak demand in passengers per hour. Use the busiest window, such as the first 30 minutes of a shift start, lunch return, or overtime release. Next, enter the bus capacity and select a realistic load factor. A load factor below 100% accounts for uneven boarding, PPE, tool bags, and comfort targets that reduce practical capacity. Then build cycle time from round-trip travel plus dwell time at each stop, security screening delays, and a recovery buffer. The recovery buffer is essential when site traffic, weather, or gate checks fluctuate.
The recommended headway is calculated so that each departure can carry the hourly demand when spread across the hour. From that headway and the cycle time, the tool estimates the minimum number of buses required. If you enter the buses you actually have, the fleet check compares achievable headway and maximum hourly capacity against your demand. This helps you decide whether to add buses, adjust staging, or split routes to reduce cycle time.
Example (matches the first row in the table above):
- Peak demand: 240 passengers/hour
- Capacity: 30 passengers, load factor 90% → effective capacity 27 passengers/trip
- Travel round trip: 18 min, dwell: 6 min, recovery: 4 min → cycle time 28 min
- Recommended headway: 60 × 27 / 240 = 6.75 min
- Buses required: ceil(28 / 6.75) = 5 buses
Use the target headway field when your site sets a service goal, such as “a bus every 5 minutes” at peak. The calculator will show how many buses are needed to meet that goal and the hourly capacity it provides. For best results, validate dwell time with a short field observation and update values after major site layout changes.
FAQs
1) What is bus headway in a construction shuttle plan?
Headway is the time gap between consecutive bus departures on the same route. Smaller headway means more frequent service, which reduces queues during peak crew movements.
2) Why use a load factor instead of full capacity?
Load factor reflects real operating conditions: uneven boarding, PPE, bags, and comfort limits. Using a realistic factor helps prevent overcrowding and reduces boarding delays at gates.
3) What should I include in dwell time?
Include boarding and alighting at each stop, badge checks, turnstiles, and any security screening. If buses queue at the gate, add average waiting time as part of dwell.
4) How do I estimate peak demand (passengers/hour)?
Count arrivals during the busiest window and scale to an hourly rate. For example, 120 passengers in 30 minutes is approximately 240 passengers/hour during that peak period.
5) What does “buses required” represent?
It is the minimum whole number of buses needed so that one full cycle can be maintained at the recommended headway. It assumes consistent dispatching and similar cycle times per bus.
6) Why add recovery or layover time?
Recovery time absorbs variability from traffic, weather, and site controls. Without it, small delays compound, headway becomes irregular, and queues grow quickly during shift changes.
7) What can I do if the fleet check shows a shortfall?
Reduce cycle time by shortening routes, adding a closer staging point, or improving boarding flow. If that is not possible, add buses or stagger shift start times to lower peak demand.