Charleston County should spend its half-cent sales tax dollars on improvements to the Interstate 26 corridor, or neighborhoods in the upper peninsula will continue to suffer.

That's the message Coastal Conservation League Executive Director Dana Beach sent Monday to County Council after a recent decision to use a large portion of half-cent sales tax revenue as leverage for state dollars to extend the Mark Clark Expressway.

"We missed a golden opportunity, perhaps once in a lifetime, to look at the future of this region," Beach said.

By the decision, Beach said, council threw out recommendations to carefully review projects proposed by the Transportation Advisory Board, a group of 14 residents appointed about a year ago to study how the money should be spent.

In the next 10 years, the area will see an additional 150,000 trips a day on roads, primarily I-26, Beach said. Unless the Charleston Neck area is taken into account, neighborhoods such as Union Heights and Rosemont will be fractured.

"What are we doing about that? Nothing," he said. "We think that is a tragedy."

Council is expected to move forward at its meeting today with a plan to dedicate a significant share of the sales tax revenue, which could generate $1.3 billion in 25 years, to six new road projects, financed through bond referendums.

None are proposed for I-26, except an extension to the new Medical University Hospital, Beach said.

Providing money for those projects will help secure matching funds from the state Transportation Infrastructure Bank for the Mark Clark extension, a $420 million project that will stretch Interstate 526 from the Citadel Mall to the James Island Connector.

County Council Chairman Leon Stavrinakis said council never disregarded the advice of the transportation board. The I-526 extension is a worthwhile project that will alleviate traffic and provide a hurricane evacuation route for residents of the islands, he said.

"We respect the Coastal Conservation League," Stavrinakis said. "They are simply opposed to the Mark Clark extension."

John Knott, the chairman of the transportation board, said the council still has an opportunity to make a decision on the board's recommendations. The board did not specify road improvement projects. It asks council to thoroughly investigate projects using a set of criteria that centers on fixing existing roads, Knott said.

"If council supports the idea and follows the decision-making process, I have no problem," he said.

Beach, who made his comments among representatives from several advocacy groups at an informal news conference, urged residents to attend tonight's meeting.

"The recourse is going to the politicians and demanding they pull back," Beach said. "They need to demand citizens' input is taken seriously."

Reach Yvonne M. Wenger at 745-5891 or ywenger@post andcourier.com.