Cost Per Mile (CPM)
Operating cost divided by distance traveled, or by hours for equipment. The most quoted fleet number and one of the easiest to misread.
Cost per mile is simple to calculate and simple to misuse. Everything depends on what is in the numerator and what the denominator actually measures.
Low utilization inflates it mechanically. A vehicle that barely moves will show a terrible cost per mile while costing the organization very little in absolute terms, and a report ranking units by cost per mile will put the fleet’s least-used assets at the top of the replace list. That is precisely backwards: the finding is that the vehicle is underused, and the answer is usually to reassign or remove it rather than to buy a new one.
For equipment the measure has to be hours, and mixing the two in one report produces nonsense. A mower has no meaningful cost per mile.
Comparisons across agencies need the inclusions checked before anything else. Whether the figure carries depreciation, overhead, fuel and administrative cost changes it enormously, and two fleets quoting cost per mile are often not describing the same thing at all.