Downtime
Time a vehicle is unavailable to the department that needs it. Usually counted in days out of service, and usually the measure a using department cares about most.
Downtime is the fleet metric that other departments actually feel. A director who has never asked about cost per mile will ask why the truck has been in the shop for nine days.
The number is only meaningful once you decide what starts and stops the clock. Time waiting for a part, time waiting for an outside vendor, time waiting for a department to bring the vehicle in, and time waiting for the department to collect it afterwards are all downtime to the user and are not all the shop’s doing. A fleet that reports total days out of service and a fleet that reports wrench-in-hand time will produce wildly different figures for identical performance.
Splitting it is the useful move. Time the shop controls is a performance measure. Time spent waiting for parts is an inventory question. Time spent waiting for a department is a policy question, and it is often the largest share, which is uncomfortable to report and worth reporting anyway.
