Opponents raised their voices within hours of Austin Independent School District approving the biggest bond package in the district’s history. In May, voters will consider footing the bill for $892 million on school improvements.

"It is an outrageous bond proposal," Don Zimmerman of the Travis County Taxpayers Union said.

Zimmerman is suspicious of the size and timing of the upcoming bond election. Now that Austin City Council elections are moved to November, bonds will be the only thing on the ballot in May.

Even when council races were included, May elections suffered from historically low turnout. Only seven and 11 percent of registered Austin voters cast a ballot in the last two elections.

"They might get this huge tax increase passed with five percent of the voters," Zimmerman said.

He warns that would open the door to special interest groups controlling the outcome.

"If you oppose anything that the district does, they will publicly attack you as being against education and against children," he said.

AISD leaders said the purpose of the bond package is to catch up with growth and fix aging facilities. The district plans to build three new elementary schools and renovate several other campuses based on a 2011 needs assessment. Students from McCallum High School urged the board to improve their dance studio.

"Essentially if the floor isn't well-kept, the girls on the dance floor could get hurt as well," AISD spokesman Antonio Lujan said.

The district plans to launch a website next week showing how the bonds affect neighborhood schools.

"You'll be able to look at the information prior to casting your vote, and you'll be able to understand the bond in full detail," Lujan said.

AISD officials say the bond will cost the owner of a $200,000 home an additional $70 a year in property taxes.

The tax burden is too great, Zimmerman said, especially following on the heels of other tax hikes. Last November, Austin voters approved $306 million in city bonds, plus more than $250 million a year on health care services associated with a new medical school at the University of Texas.

Early voting in the AISD bond election runs April 29 through May 7. Election day is May 11.