Nearly two-thirds of the Columbus schools' buses are more than 15 years old, which means they exceed their recommended lifespan and cost more to maintain.
The district's oldest buses, which date to 1986, cost nearly 10 times as much per mile to maintain as its newest buses. Those expenses and rising fuel prices have contributed to a rapid rise in the district's transportation budget, which grew more than 13 percent this school year.

The state of the district's bus fleet is one of the factors being considered by a committee that will recommend whether the Columbus schools should place one or more tax requests on the ballot this year.

The district could use money from a bond issue or an operating levy to help pay for new buses and fuel, which this year has averaged $3.04 per gallon.

Administrators presented information about the bus fleet to the committee last month.

Compared with some other school districts', Columbus' fleet of 543 buses is archaic. Only 2 percent of the Cleveland school district's buses are more than 15 years old. In Akron, 5 percent of the buses are that old.

Pete Japikse, head of student transportation in the Ohio Department of Education, said harsh weather and salted streets can cause school buses to wear out faster up north. Mileage and maintenance costs are a better gauge when deciding whether a bus should be replaced, he said.

"What we've discovered is the maintenance cost of a vehicle will increase drastically after you get over 200,000 miles," Japikse said.

About 62 percent of the Columbus school district's buses have been driven more than 200,000 miles. Columbus spent about $1.6 million on school-bus maintenance during the 2006-07 school year.

School buses cost about $80,000 apiece, Japikse said, and that is rising rapidly because of new emissions standards and the increasing cost of steel. The price could reach $100,000 as soon as 2010, he said.

To add to the crunch, the state has slashed the money it gives school districts to purchase buses. In 2002, Ohio provided $32 million; now it's $5.8 million, Japikse said.

Columbus schools Chief Operating Officer Larry Hoskins told the district levy committee that replacing all of the district's buses over 11 years would cost $55.8 million.

The district also is preparing a cost analysis of eliminating the use of private bus companies, which primarily have been used to handle charter- and private-school students, Hoskins said. Although district buses handle the majority of routes, the schools are paying private bus companies more than $13 million this fiscal year.