North Dakotans are setting aside more money each month to compensate for increased prices at the pump, but estimating individual fuel costs is nothing compared to fueling a fleet.

North Dakota AAA spokesman Gene LaDoucer said recent unpredictable swings in gas prices have made budgeting difficult for government departments that rely on a fleet of vehicles.

"It's hard to say what gas prices are going to do," LaDoucer said. "We just recently had the highest prices ever paid in the United States and in North Dakota."

Bismarck Police Lt. Dan Donlin said the Bismarck Police Department's average cost per mile jumped from 24 cents to 31 cents per mile between 2005 and 2006.

In 2005, the Bismarck Police Department's 43-vehicle fleet traveled just more than 700,000 miles, with an annual fuel cost of $117,000. Last year, police department vehicles went about 15,000 less miles, but their total fuel cost increased by more than $20,000.

Bismarck Police Deputy Chief Keith Witt said the police department budgets for gas based on the previous year's totals. If the police department exceeds its budget, the city must compensate for the excess fuel cost.

"We do what we can to conserve as much as we can," Witt said.

The Burleigh County Sheriff's Department's fleet also experienced an increased cost per mile last year, but unlike the Bismarck Police Department, the fleet's annual fuel cost dropped by about $5,000 between 2005 and 2006.

Capt. Les Witkowski said the fleet cut more than 100,000 miles from travel in 2006 compared to 2005. He attributes this mileage loss to decreases in patrol staff over the past few years.

Witkowski said he's confident the county can stay within its 2007 budget.

"For 2008, it's hard to predict what gas prices are going to be," Morton County Sheriff Dave Shipman said.

He said the department's oil and gas budget has increased every year since 2003, nearly doubling in the last 15 years.

The Morton department, which spent just more than $56,000 on gas for its fleet last year, has stayed within its 2007 budget so far, Shipman said.

However, summer could bring trouble for area law enforcement fuel budgets. LaDoucer said he doesn't expect to see the highest gas prices of the year until July or August.

"If you're getting 60 percent swings over a short period of time, budget (errors) are magnified," he said.

According to the Department of Transportation, the state motor pool, which includes the state Highway Patrol fleet, saw a $550,000 increase in fuel costs between 2005 and 2006.

(Reach reporter Alyssa Schafer at 250-8264 or alyssa.schafer@;bismarcktribune.com.)