Indiana's attorney general said Monday that state law doesn't allow public school districts to charge students a fee for taking the bus to and from school.

That could pose a problem for school districts around the state that had been looking at the fees as one possible way to help them out of a financial bind caused by property tax caps and a $300 million cut in state education spending.

The opinion said school districts have no legal authority to assess and collect a fee for transportation to and from school so a student can receive a public education. Further, it says that transportation is part of "a uniform system of public education in Indiana."

"Such a fee is unconstitutional," the opinion said. It didn't specifically address charging bus fees for extracurricular activities.

Molly Butters, a spokeswoman for Attorney General Greg Zoeller, said official opinions are intended to serve as guidelines for state officials and aren't legally binding.

"It's an opinion, nothing more than an opinion or an interpretation of the law," she said.

Dennis Costerison, executive director of the Indiana Association of School Business Officials, said the opinion might not be binding, but it could give ammunition to a parent who decided to sue their school district over bus fees.

In either case, the nine-page document presents a complication for districts like Franklin Township Schools on the south side of Indianapolis, which had been counting on charging a bus fee of about $75 per rider beginning this fall. Districts in Hobart and Munster in Lake County already charge for transportation, he said.

The Associated Press left a phone message seeking comment from Franklin Township Schools Superintendent Walter Bourke.

The growing district, saddled with construction debt, had been hit hard by a 1-percent residential property tax cap that went into effect this year, as well as the state budget cuts announced last year, Costerison said.

"They're going to have to go back to the drawing board and try to figure out how they're going to take the dollars they have for regular transportation and make it work," he said.

Costerison said that the law doesn't require school districts to provide transportation except for special needs students, and Franklin Township and other districts might be forced to set strict limits — perhaps providing bus rides only for students who live more than a certain distance from school.

"The worse-case scenario is you don't have transportation at all," he said.