ATLANTA (AP) - Unofficial returns show the transportation tax referendum faces an uphill battle in metro Atlanta.

With 57 percent of precincts reporting, 64 percent of voters rejected the tax, compared to 36 percent in favor.

The proposed penny sales tax to fund billions in transportation projects over the next decade was a draw for many voters in Tuesday's primary election. The issue was on the primary ballot in 12 districts around the state.

The Atlanta region stands the most to gain if the measure is approved there.

Supporters include Gov. Nathan Deal and Atlanta Mayor Kasim Reed, who tied the tax to Georgia's economic future and promised the infrastructure projects would ease traffic for frustrated commuters.

Critics derided the proposal as an unfair tax on the poor that doesn't solve sprawl.