While a citizens' review panel was going through a seven-month examination of Salt Lake County's vehicle usage, the county auditor's office was doing a more limited "performance audit" — and came to some of the same conclusions.

"As we started looking at it, we said, 'Boy, this really needs some review,' " internal audit director Jim Wightman said.

The audit, released Monday, concludes primarily that fleet management overstated its costs, resulting in a steadily increasing surplus of millions of dollars.

The citizens' review panel concluded the same thing, saying the surplus hid fleet inefficiencies. The panel determined the fleet had $9 million more than it needed to reasonably conduct business.

The auditors also said the fleet had too much money but said it was more in the range of $6 million.

According to the auditors, fleet management overstated the cost of vehicle replacement by assuming a 6 percent inflation rate when the going rate was more like 0 to 2 percent, as well as overestimating maintenance costs.

Whereas the citizens' review panel was skeptical of the county's rapid-replacement program, the auditors were more positive toward it — particularly with regard to sheriff's cruisers, which are sold after a single year of use to police agencies across the country.

"It's like you set up an eBay for these vehicles ahead of everyone else," Wightman said.