RALEIGH - Higher fuel costs are forcing Wake County school leaders to dip into their rainy-day fund to keep school buses on the road.

The school board voted Tuesday to take $2.2 million out of emergency coffers to pay for higher-than-expected diesel fuel costs. Administrators are also blaming a small part of the extra costs on having to bus students who left year-round schools in favor of those with traditional calendars.

"I don't see there are other options," said school board member Lori Millberg.

The vote leaves the district with about $15 million in the rainy-day fund to cover emergencies. County commissioners have criticized the school district for having the fund, saying it should be up to the county to cover those emergencies.

But school board members said the diesel fuel emergency showed why they need a reserve fund under their control.

Administrators had budgeted fuel costs for the buses at $1.97 per gallon. But they say diesel is costing the district $2.73 a gallon -- a cheaper price than the public pays because the district doesn't pay sales taxes and buys fuel in bulk under a statewide contract.

"There's difficulty in knowing where fuel prices are going," said Don Haydon, the district's chief facilities and operations officer.

With the fleet running 17 million miles each school year and the 878 buses averaging 6.6 miles a gallon, higher prices for diesel were in danger of busting the district's $4.8 million fuel budget.

Beverley Clark, vice chairwoman of the school board, said the rising cost of fuel illustrates the need for more hybrid buses. As part of a national pilot program, Wake received one hybrid electric bus this year. The vehicle is getting 50 percent more miles a gallon.

Additionally, administrators said buses are running 812,694 miles this school year for children who opted out of year-round schools. The district was forced to allow those students to opt out after a judge ruled that families can't be forced to attend year-round schools.

Haydon said these additional bus routes are responsible for up to 10 percent of the increased expenditure for diesel.

But Dawn Graff, a co-founder of Wake CARES, the group that sued over year-round schools, said Wake could have reduced the busing costs by sending students to traditional-calendar schools closer to their homes. Graff said any extra costs from busing students who left year-round schools are outweighed by the amount spent busing children for diversity.

"If they didn't have to bus children from downtown Raleigh to Apex, then they could spend more on education," Graff said.

School board member Susan Parry said that the majority of elementary students go to a school near where they live.

School board member Carol Parker asked how much money is spent on busing students for diversity. Haydon said he didn't think that number had been determined.

The diesel fuel vote was 7-1, with board member Ron Margiotta the lone dissenter. He said the district should have found the money somewhere else.