A police officer's Ford Crown Victoria often doubles as an office.

An office that has to be heated in the winter, air-conditioned in the summer and go from zero to 60 in seconds. All that takes gas.

Virginia state troopers burn about 200,000 gallons in their cruisers each month. Sheriff's deputies in one Southern Maryland county drive more than 430,000 miles a month, and state police officers there routinely use a tank of gasoline on every eight-hour shift.

As fuel prices rise steeply across the nation, the region's police departments are bracing to blow their budgets and, in some cases, are considering strategies to conserve.

Montgomery County has discussed reviving a program from a decade ago that required police officers to park, turn off their cars and patrol by foot for 10 minutes each hour.

Since last year, the Maryland State Police has discouraged troopers from idling when monitoring a closed road and have encouraged them to use radar from a parked car, instead of cruising, to catch speeders.

"One thing's for sure: We can't stop patrolling," said Sgt. Thornnie Rouse, a spokesman for the Maryland State Police.

Unlike some workers who can choose to ride the Metro or a bus to the office when gasoline prices climb, a police officer's car is critical to the job.

"They don't have a desk at a police station. They live and work in their cruiser," said Nick Tucci , director of the police management and budget division in Montgomery. "That's their lifeline."

Patrol officers write reports, search criminal databases and send e-mails from computers in their cars. Those devices, in addition to radios and emergency lights, can run on batteries when the engine is turned off.

But the battery power lasts only so long. Police said officers prefer to idle, and that uses gas -- lots of it.

The average price of a gallon of regular gas in the United States was $2.59 yesterday, up 39 percent from a year ago, when the average was $1.87. In the Washington region, the average price was up to $2.65 -- the highest price since AAA began recording such numbers in 1974. The agency provides prices in its daily fuel report.

City and county governments, which typically purchase the fuel for the region's police cruisers, pay less. For the past 20 years, 15 to 20 jurisdictions have joined to purchase fuel at a discount through the Metropolitan Washington Council of Governments.

But those prices, too, have increased. On Aug. 1, the cooperative's price was $1.7459 a gallon. The price through Sept. 4 is $2.0016, said Carl Kalish, who coordinates the program.

In Virginia, nearly 1,900 state troopers have vehicles assigned to them, and at any given time, hundreds are patrolling the commonwealth's interstates and highways. Each year, they drive a total of about 40.8 million miles -- or about the equivalent of 171 trips to the moon -- and use about 200,000 gallons a month, said Col. Steve Flaherty, Virginia State Police superintendent.

At today's high prices, he said, that translates to an estimated $1.2 million above the annual fuel budget.

"It's a lot of money, a lot more than we anticipated," he said, adding that the agency had anticipated that it would overspend its projected budget of $3.7 million, though not by so much.

Like the counties, the state uses it own pumps maintained by contractors. The average price per gallon this week was $2.05. Still, as costly as fuel has become, Flaherty said, commanders have not issued instructions to the troopers to conserve fuel.

"The last thing we would ever do is cut patrols," he said in a phone interview from Richmond.

In Prince William County, too, the figures reveal a situation far more expensive than police anticipated. In July 2004, the county police department's 392 vehicles consumed about $38,245 worth of gas. Last month, the price increased by at least 20 percent.

"Our officers are in their cruisers all day, every day," said Sgt. Kim Chinn, a police spokeswoman. "They drive about 4.1 million miles a year. It's going to cost a lot."

Although the steep increase in gas prices has surprised many departments, officials from several Northern Virginia jurisdictions agreed that it has had little effect on their mandates. They respond to calls regardless of how much it costs, they said.

That sentiment was echoed across the region. Lt. Tom Chase of the Frederick police force said past shortfalls have not "prohibited us from providing our level of service." After budgeting $121,400 last year, the department spent $179,345 on about 95,000 gallons of fuel for 136 vehicles. This year's budget is $160,000.

Concerns about rising prices were less pronounced in the District, where police beats cover much less territory. D.C. Police Chief Charles H. Ramsey said he has not considered cutting cruiser patrols or asking officers to change their routines.

D.C. police get their gasoline at a discount through the Defense Energy Supply Center, which sold unleaded fuel to the District on Aug. 15 for $2.0347 a gallon, said Janis Bolt, spokeswoman for the city's Office of Contracting and Procurement.

In the outer suburbs, Charles County's 240 sheriff's deputies were driving more miles and spending more money on gas even before the recent price increases.

For the fiscal year ending June 2004, Charles spent $373,142 to patrol 5.1 million miles. Through June 2005, the county spent $463,799 for deputies to drive 5.2 million miles. This year, the sheriff's department has budgeted $453,600.

"Obviously, that's not going to get us there," Captain Joe Montminy said.

Montgomery's 1,300 officers are encouraged to spend about 30 percent of each 10-hour shift talking and interacting with people in the community, doing what is called "proactive policing."

But a decade ago, and during an oil embargo in the 1970s, the department required officers to park for at least 10 minutes each hour to conserve gasoline. That idea came up again this week, Tucci said, as department leaders pondered the climbing prices.

Gas prices are not so high that the department would immediately change how it operates, Tucci said, "but we're thinking about it, because it could come to that."

Staff writers Petula Dvorak, Nelson Hernandez and Jonathan Abel contributed to this report.