AUBURN – Twin Cities growth may depend on a new Lewiston turnpike interchange, according to traffic engineers and citizens Tuesday night.

A group of about 40 studied eight plans for a new downtown turnpike interchange at the Androscoggin Valley Council of Government’s Auburn office. Plans called for putting an interchange somewhere between exits 75 and 80 of the Maine Turnpike – along Riverside Drive or South Main Street in Auburn, or along River Road in Lewiston.

“No matter what you do on the Auburn side, it looks like you’re building into a bottleneck,” said Roland Pelletier, of 405 S. Witham, Auburn. “You have to build in Lewiston to make any difference.”

The growth is coming, according to Bruce Hyman, of Wilbur Smith Associates, a traffic engineering firm. Computer models show another 9,700 cars using the Lewiston turnpike interchange, exit 80, by the year 2025. The models put another 3,000 cars on Auburn’s exit 75.

A downtown interchange would be designed to take some of that traffic off of those exits, Hyman said.

“We’re not looking for that one silver bullet to solve every transportation problem in Lewiston and Auburn,” he said. “We’re looking at all eight plans to see how feasible any of them are.”

A combination exit on both sides of the river made the most difference, according to studies. A full exit on Riverside Drive in Auburn would be used by almost 10,000 cars daily while a southbound exit on River Road in Lewiston would see as many as 17,000 cars daily.

“And because it points to Auburn, we find that the turnpike becomes a second bridge for the cities,” said Traffic Engineer Tom Errico.

A full Lewiston exit on River Road had a great impact as well. An estimated 18,750 cars would use it daily. It would pull about 10,000 cars off of its Lewiston neighbor and another 2,000 from Auburn.

Auburn only interchanges, on Riverside Drive, South Main Street or between the two, would pull between 2,000 and 6,000 cars away from the Washington Street turnpike exit and none from Lewiston.

“It looks to me like the demand in Auburn just doesn’t warrant a new interchange,” said Denis Bergeron of 23 Dexter Ave. in Auburn. “It seems that if you put the traffic anywhere but on Washington, you just make the traffic downtown worse.”

Doreen Jordan, of 42 Hector St. in Auburn said she doubted Riverside Drive could handle the increased traffic and was sure the South Bridge couldn’t.

“I really think all of this belongs in Lewiston,” she said.

A new bridge, built somewhere in between the turnpike and the south bridge would be used about 6,000 times daily by 2025, Hyman said.

Engineers and transportation officials will take the comments and include them in the study. A second public hearing is scheduled for late April or early May. Then officials will submit the feasibility study to the state. The group hopes to have approval to build the new exit in about 2010.

staylor@sunjournal.com