Have someone in accounting gather the mileage and driving records of your company trucks every week to calculate the percentage of miles paid by customers and percentage of miles not billed (cost to the company). Ask questions concerning first about the profitability of the paid trips. Make sure the rates have been raised properly to keep up with costs. Analyze all of the trips that were not billed to a customer and ask why the truck was on the road. Do you not have enough trucks so you must drive them to other facilities constantly? Do you use your trucks for delivering your own goods when there are cheaper alternatives? Graph the paid miles by driver and look for anomalies every week. Cut out or reduce the unpaid trips.