Track four separate indicators — downtime rate, availability, repair turnaround, and unscheduled repair rate — with consistent definitions, measured monthly. Downtime tells you how many duty hours you lost; availability tells you whether the mission was covered; turnaround tells you how fast work orders close; unscheduled rate tells you whether the work was planned. A single availability or turnaround figure won’t explain why vehicles are unavailable, and the fastest way to misdiagnose a shop is to manage all of this from one number.
Use the same definitions every month so changes in the results stay interpretable:
| Measure | Formula | Target | Owner |
|---|---|---|---|
| Downtime rate | Asset-hours unavailable during scheduled duty ÷ scheduled-duty asset-hours × 100 | ≤5% | Shop Supervisor |
| Availability | Asset-hours available for the mission ÷ total possible asset-hours × 100 | ≥95% overall; 97–98% mission-critical classes | Fleet Manager |
| Repair turnaround | Work order open to work order close (elapsed time, not labor time), for WOs closed in the period | ≥80% closed within 24 hours; ≥90% within 48 hours | Shop Supervisor |
| Unscheduled repair rate | Unscheduled work orders ÷ total work orders × 100 | ≤30% | Shop Supervisor |
When you log downtime, record the reason with it — maintenance or repair, waiting for parts, vendor work, accident, or administrative delay. Those reason codes are what make the monthly review useful. These four sit alongside the rest of the numbers in our fleet KPI benchmarks guide.
The two measures use different denominators. Downtime is counted against scheduled duty hours; availability is counted against total possible asset-hours in the period. A vehicle that breaks down overnight, when it wasn’t scheduled to work, hurts neither number — but a vehicle down for two hours in the middle of its route hurts both. Treat them as two views of the fleet, not one number and its inverse.
Availability can also look fine while the underlying work is unhealthy. If PM compliance is slipping, vehicles are still on the road — right up until deferred services turn into breakdowns. That’s why the unscheduled repair rate belongs in the same monthly review: unscheduled repairs add downtime through diagnosis, parts sourcing, and towing, and they pull technician time away from scheduled PM, which creates the next round of unscheduled repairs.
Turnaround is elapsed time, so a slipping result doesn’t automatically mean the shop is slow. Before assigning a cause, separate repair time from waiting time and identify where the elapsed hours accumulated:
Don’t assume technician coverage is the problem from the total turnaround alone — it’s one possible cause, and the delay codes will tell you if it’s the real one.
The monthly review should end with an action per cause, not just a number. For parts-related delays, examine supplier performance and inventory availability: run regular inventory counts to verify stock against records, identify shortages, and proactively restock the most-used parts. Fleet360’s parts and inventory tools track stock, usage, and reorder points from the same work orders that drive your turnaround numbers.
Then keep a simple review record: one row per measure per period, with the definition, result, target, cause category, and follow-up action. Keep the definitions stable — if the formula changes, you can no longer tell whether the fleet changed or the math did. Fleets using Fleet360’s maintenance and repair tools get downtime reasons, turnaround, and unscheduled rates from their work orders automatically.
See Fleet360 in Action
Downtime reasons, turnaround, and availability from your real work orders — no spreadsheets.
No. Downtime is measured against scheduled duty hours, while availability is measured against total possible asset-hours in the period. The denominators differ, so track them as two separate indicators.
The Shop Supervisor owns downtime, repair turnaround, and the unscheduled repair rate. The Fleet Manager owns availability. All four are reviewed together monthly.
Time an asset is unavailable during scheduled duty, recorded with a reason: maintenance or repair, waiting for parts, vendor work, accident, or administrative delay. The reason codes are what let you fix the right problem.
Of the work orders closed in the reporting period, at least 80% closed within 24 hours and at least 90% within 48 hours. Measure elapsed time from work order open to close — not technician labor time.