Mine was a sister/brother ownership, parents still active but slowly moving out to retire. Owned 3 tractors, about 100 trailers, used about 50-60 owner/operators. Mostly machinery/equipment hauling, were starting some milk runs for Ford.
As I recall most of our measurables came out of the ISO requirements - delivery, customer satisfaction, etc. Auditor suggested cost/mile as another measurable.
Let me know if you have any questions.