The Fairfax County Planning Commission on Tuesday defended its plan to levy new taxes on residents and developers to pay for the massive, $3.1 billion redevelopment of Tysons Corner while seeking only "modest" funding from the state.

Speaking to the county Board of Supervisors, officials announced their plans to impose a 7-cent to 9-cent property tax increase on Tysons Corner properties that would be placed in a special tax district. That tax would raise about $250 million to fund roads around Tysons. The county would collect about $250 million more from businesses seeking to redevelop the area.

The boundaries of the special tax district haven't been set, but will eventually ensure that "the folks that benefit most" are taxed, said Walter Alcorn, vice chairman of the Planning Commission.

The new taxes being imposed on Tysons developers is in addition to the $865 million they will pay to build streets and whatever they spend on other amenities, like community centers and ball fields.

County officials have already approved some of the planned projects for Tysons Corner, including the massive expansion of Capital One's headquarters, and have another dozen projects up for approval this month. But board members cautioned against trying to collect too much money in advance of construction.

"People are going to want to see things in the ground right away, not major improvements 15 years down the road," said Supervisor Jeff McKay, D-Lee, who proposed a phased plan that would allow taxpayers to see progress being made.

All county taxpayers would have to foot the remaining bill of $1.7 billion needed to fund an expansion of local and regional bus routes and road improvements outside of Tysons Corner, including new ramps from the Dulles Toll Road and new roads parallel to Route 7.

The county will see about $134 million from the state, or just over 4 percent of the overall cost of the project, said Alcorn. He called it a "fairly modest request."

Chairwoman Sharon Bulova applauded the "historic" plan, which comes just two years after the board voted to completely redevelop Tysons into a mini-city of high-rises, hotels and restaurants along Metro's new Silver Line.

The Fairfax board will hold a public hearing on the Planning Commission's final recommendations at its Oct. 16 meeting.