Lowcountry officials traveled to Columbia this week on a high-stakes mission: bring home millions of dollars in state road money.

They came home celebrating the promise of money to come. The Lowcountry is at the top of the list for more than $340 million from the state Infrastructure Bank.

The money would clear the way for a major industrial park in Berkeley County, improve congested traffic arteries around Summerville and expand the Interstate 526 interchange at U.S. Highway 17 in Mount Pleasant.

"This is the most important meeting I've ever attended," Dorchester County Council Chairman Larry Hargett said Wednesday. "It doesn't get any bigger than this. This is where the rubber meets the road."

The bank promised Dorchester County $213.3 million and Berkeley County

$115.8 million as soon as money becomes available. There's no more money in the bank until the Legislature votes to replenish it.

The Infrastructure Bank is under the state Department of Transportation. Much of the money comes from sales taxes on new vehicles.

The bank had enough money left to grant Mount Pleasant's request for $11.4 million immediately. But that request, along with ones from Horry and Aiken counties, took the balance down to zero, according to board members.

For Berkeley County, the stakes were more than 18,000 jobs at a new industrial park in the Jedburg area west of Summerville.

The county needs $115.8 million from the state to widen I-26 and other roads to handle the traffic. One of the developers told the board that without some assurance of state money within a few months, they will have to pack up and build somewhere else.

"We can't move forward without these improvements," said Kurt Grantham with Trammell Crow, which is developing Omni Commerce Park, one of 13 projects there. "We have to have some assurance within the next couple months."

The board approved Berkeley County's request as soon as money is available. The decision left county Supervisor Dan Davis with mixed feelings.

"I think everybody was hoping there might be some money so we might begin," Davis said. "But at least they didn't say no. It was the next best thing that could happen for us."

Mount Pleasant officials said the I-526 interchange is a bottleneck for moving cargo from the Wando shipping terminal to the rest of the state. They said Mount Pleasant needs the state money because land values near the interchange have escalated in the couple years since the town started planning the project.

Rep. Annette Young, a Summerville Republican who was at the meeting, said she's optimistic that lawmakers will approve more money when the Legislature reconvenes in January.

"We've finally got DOT's attention," Young said.

Berkeley County would need money first. Dorchester County can keep using bonds from the penny-sales tax increase the county started collecting for another year or two.