The rising cost of fuel is hitting school districts hard. Some are planning for increase of more than 50 percent.

Austin ISD shuttles some 18,000 kids to school each day, and the district's pain at the pump is magnified -- 360 buses run each day during the regular school year.

It adds up to 6 million miles a year for the fleet, which means this year's fuel budget has risen by more than $794,000.

Austin is not alone in this. Both Eanes ISD and Leander ISD are doubling their numbers this year. That's -- in part -- because they spent more than they anticipated last year.

Lake Travis ISD is budgeting a $193,000 increase -- a 57 percent jump.

At Round Rock ISD -- a $740,000 jump and 30 percent increase.

And finally Del Valle ISD is budgeting an added $98,000 -- which translates to a 15 percent jump.

Austin ISD is hoping to add more hybrids to its fleet. The first plug in hybrid diesel bus started running routes in October.

"Right now it shows about 30 to 40 percent fuel efficiency," said Kris Hafezi, AISD Transportation Department. "But like any other new technology, there are bugs in that."

All the maintenance has been under warranty and the price has dropped on the hybrids.

Even though they still cost $100,000 more than a standard bus, the district plans to add one or two more next year.

There is some relief -- school districts don't have to pay tax on fuel.

Right now, diesel is averaging $4.90 per gallon in the Austin area, but AISD is paying only $3.95 a gallon.