WASHINGTON -- The wheels on the bus aren't the only things going round and round.
The dials on the fuel pump are spinning, too, for school districts that face soaring costs just as 25 million children get back on the bus for a new school year.
Most buses use diesel fuel, which has jumped 74 cents a gallon since last year. School districts now pay $2.25 to $2.40 a gallon on average, a figure that keeps climbing because of summertime demand for fuel and the escalating price of crude oil.
To offset the costs, districts are stripping money from classrooms, trimming bus routes, cutting field trips, and raiding cash reserves. Some are considering whether to charge fees for bus service or to ask more students to walk to school.
Ultimately, however, the buses must keep running. School transportation is mandatory in most states, and buses account for more than 8 billion trips to and from school each year.
One bit of good news: Buses are the safest form of school travel, and when gas prices get this high, more teenagers ride the bus to save money, often at the behest of their parents.
''I think our new back-to-school slogan is: 'Fuel prices got you down? Take the school bus, and save your gas for the weekend,' " said Robin Leeds, an industry specialist for the National School Transportation Association, which represents private school-bus contractors. Many of those private contractors are absorbing some of the added costs themselves, she said.
Overall, the price of unleaded gasoline is roughly $2.55 a gallon nationally, up 68 cents from last year, the Energy Department says. Diesel fuel is at $2.57 a gallon, up 74 cents from a year ago. Those prices recently went up 16 to 18 cents per gallon in a week.
Schools get a discount because they buy in such large quantities and don't have to pay government fuel taxes.
Then again, the average driver isn't filling up a tank of 60 or 90 gallons, driving a vehicle that gets 7 miles per gallon, and hauling 65 passengers around town.
In South Carolina, the Education Department buys more than 12 million gallons of diesel fuel each year for its 5,000 buses. Each time the fuel rate goes up a penny, it costs the state about $120,000. At the current rate -- the department pays $1.94 a gallon -- the agency will bust its budget by $1.4 million and will have to ask the governor and lawmakers for help.
''We're wishful thinkers. We hope the price will come back down," said Donald Tudor, the department's transportation director.
Prices are expected to ease but only somewhat when the overall demand slows after Labor Day.