As voters in Porter and St. Joseph counties prepare to vote Tuesday on whether to create a Regional Transportation District, some public officials suggested the new district -- if approved -- would replace the existing Northwest Indiana Regional Development Authority.

Bill Hanna, the RDA's executive director, said last week he had not heard the claim that the RDA would be eliminated if voters authorize the proposed Regional Transportation District.

While the RDA has some transportation goals and would partner with the transportation district, he said its mission extends beyond that issue.

Porter County Council member Karen Conover is among those under the impression the RDA would disappear if the referendum wins voters' favor.

"It's going to be one or the other," she said.

While the idea of rolling the two groups and any corresponding taxes into one is not included in the RTD legislation approved last summer, Valparaiso Mayor Jon Costas said the move is a possibility.

The consolidation would depend in large part on which, if any, counties decide to join the RTD and what shape the group takes in the end.

Porter County residents pay a 0.25 percent income tax to generate the $3.5 million the county pays in annual RDA dues. The county currently is suing to withdraw from the agency.

The transit district, proposed for Lake, Porter, LaPorte and St. Joseph counties, would allow for the creation of a proportional income tax in each county to fund a regional bus system for Lake and Porter counties, pay for South Shore operations and finance commuter rail extensions to Lowell and Valparaiso.

Only Porter and St. Joseph counties are complying with the state mandate to host the special election, and voters in at least two counties of the four must approve the referendum for the RTD to be created.

Referendum question: A special election in Porter and St. Joseph counties to decide the fate of a proposed Regional Transportation District is scheduled for Tuesday. Voting hours at polling locations are 6 a.m. to 6 p.m.

The ballot question reads, "Shall there be created the Northern Indiana Regional Transportation District under IC 8-24 to provide a regional rail system serving Lake, Porter, LaPorte, and St. Joseph counties and regional bus public transportation system serving Lake and Porter counties with Porter County becoming a member of the district?"