Parking Supply Calculator

This calculator estimates peak parking spaces by converting people to vehicles, then adding supporting vehicle needs. It rounds up to ensure enough stalls during peak conditions.

• Worker Vehicles = Peak Workers × (Drive Share ÷ 100)
• Worker Spaces = ceil(Worker Vehicles ÷ Avg Worker Occupancy)
• Visitor Spaces = ceil(Peak Visitors ÷ Visitor Vehicle Occupancy)
• Service Spaces = Service Vehicles (Peak)
• Base Total = Worker Spaces + Visitor Spaces + Service Spaces
• Accessible Spaces = either ceil(Base Total × Accessible Rate ÷ 100) or a fixed number
• Recommended Total = ceil((Base Total + Accessible Spaces) × (1 + Overflow ÷ 100))

1. Enter your expected peak on-site workers for the busiest hour.
2. Estimate what percent will arrive by vehicle.
3. Set average occupancy based on carpooling expectations.
4. Add peak visitors and an average visitor occupancy.
5. Include service and management vehicles present at peak.
6. Choose an accessible-stall method: percent or fixed requirement.
7. Apply overflow to cover shift overlaps and unexpected demand.
8. Click calculate, then export results to CSV or PDF.

1) Why parking supply matters on active sites

Parking demand on construction projects fluctuates by trade mix, shift overlap, and inspection schedules. Under-supplying spaces can push vehicles into haul routes, emergency access lanes, and material laydown areas, increasing near-miss risk and slowing deliveries. Over-supplying wastes valuable staging space and may complicate traffic control. A structured estimate helps balance safety, productivity, and site logistics.

2) Build a realistic peak-demand dataset

Start with peak headcount by hour (not daily averages). For example, a mid-rise package may peak at 120 workers near concrete pours, while fit-out can peak later with multiple subcontractors. Capture planned visitor activity such as client walk-throughs and third-party testing. Record typical carpooling assumptions (worker occupancy) and note when public transport reduces drive share.

3) Convert people to vehicles using mode share and occupancy

The calculator estimates worker vehicles as workers × drive share. It then divides by average worker occupancy and rounds up to produce worker spaces. Visitors are converted using visitor occupancy, which is often higher than workers when consultants arrive together. Add service vehicles for supervisors, maintenance, and fleet pickups that remain onsite.

4) Accessible stalls and contingency allowances

Accessibility can be planned as a percent of the base total or as a fixed requirement. After adding accessible spaces, apply an overflow percentage to cover shift changes, unplanned inspections, and weather-driven schedule compression. A common starting point is 10% contingency, then refine based on observed peaks.

5) Use results to shape the traffic plan

Treat the recommended total as a target for striping, signage, and gate control. If the required count exceeds the available footprint, mitigate with staggered start times, carpools, shuttle runs from offsite lots, or defined delivery time windows. Re-run scenarios as staffing plans change and keep exports with your site logistics records.

1) What should I use for drive mode share?

Use recent site observations or workforce surveys. If unknown, start with 50–70% and adjust after one week of monitoring, especially if transit, shuttles, or carpools are encouraged.

2) How do I choose worker vehicle occupancy?

Solo driving is 1.0. If carpools are common, use 1.2–1.5. Confirm with trade leads, because early-morning start times often reduce carpool participation.

3) Why are results rounded up?

Parking stalls must be whole spaces. Rounding up prevents shortages during peak arrivals, minimizing unsafe overflow into roadways, crane pads, and pedestrian routes.

4) Should visitors be included even if visits are short?

Yes. Even short visits can overlap and block circulation. Estimate the maximum number of visitors at once, especially for inspections, audits, and client walk-throughs.

5) How should I handle delivery trucks and queueing?

Use service spaces for vehicles that park onsite. If trucks queue at gates, add separate queue bays outside the calculation and manage them with scheduled delivery slots.

6) Is accessible parking always a percentage?

Not always. Some projects have fixed requirements from the owner or local policy. Use the fixed option if you must provide a specific minimum count.

7) What overflow percentage is reasonable?

Many sites start at 10%. High-variability projects may use 12–20%. Reduce overflow after measuring actual peaks and implementing controls like staggered shifts or shuttles.