The commissioners decided to draft a resolution in support of the exit. It will be considered at the Aug. 28 meeting.
The Berkeley County Development Authority and the Eastern Panhandle Home Builders Association have joined the chamber, the hospital and major employers in backing a new exit, rather than some of the other options.
Those options include improving the existing roads to the hospital and construction of a service road between exits 13 and 16. After the highway department study is completed around November, a decision would be up to the state, which then would seek federal funding and approval.
"It's not just the issue of city hospital," said Gene Leonard, who chairs the interchange coalition.
Growth has led to traffic congestion along East King Street, Tavern and Old Mill roads and other arteries, he said.
Leonard told the commission he recently saw aerial photographs of the city taken 10 years ago and last year. He said the "mind-boggling" growth has outstripped the capacities of roads and utilities.
"I think we already have major gridlock," Leonard said after the meeting.
Supporters of the interchange have also sought the support of state and federal elected officials.
A simple diamond interchange would cost about $10 million and it could be several years before construction begins, a federal highway official said in June.