The Mackay Creek bridge, the first span crossing from Bluffton to Hilton Head Island, was built in 1956 and is still safe, but “structurally deficient” and is up for replacement. DEAN ROWLAND

Fasten your seatbelt; here we go again.

After more than a year of exhaustive studies and input from the town of Hilton Head Island and Beaufort County, the South Carolina Department of Transportation (SCDOT) will release its findings about U.S. 278 corridor improvements Sept. 19 at a public hearing on the island.

Its overall objective is to address structural deficiencies at the eastbound Mackay Creek bridge link, recommend the best ways to accommodate increased traffic capacity and mobility on the four-span bridge, reduce congestion, and identify the impact on the environment and in the north-end communities, including some historic Gullah neighborhoods.

The proposal focuses on the 4-mile corridor that stretches from Moss Creek Drive in Bluffton to Spanish Wells Road on the island.

The estimated improvement project will cost $240 million and will be funded by federal, state and local sources.

At the open house-style meeting, which begins at 5 p.m. at the Boys and Girls Club of Hilton Head Island, 151 Gum Tree Road, SCDOT will present a range of improvement alternatives and analyses results of its studies.

“We’ll be presenting a purpose and needs statement for the project, which describes the reason and the need for the project,” said Craig Winn, SCDOT program manager for the Lowcountry Regional Production Group. “We’ll provide an update on the alternative analysis process; we’ll present a full range of alternatives and the evaluation criteria for those, and a draft reasonable alternative.”

The team began its work last summer, after the national highway system put the Mackay bridge span on its replacement list in 2016.

His team amassed 14 alternatives and reduced it to six, which will be on the agenda in September.

The bridge is “structurally deficient but safe, and it’s up for replacement,” Winn said. That portion of the bridge was built in 1956.

“We worked with Beaufort County to make it the entire project, because originally it was just the Mackay bridge replacement,” Winn said. “We agreed to look at the entire corridor.”

David Johnson, chairman of the 15-member 278 corridor committee for the town, agreed that the bridge replacement was the starting point. The federal government committed $40 million to $43 million for the span replacement.

“The county said, ‘Wait a minute, if you’re going to do a two-year replacement on that span, why not do an environmental assessment on the whole corridor,'” he said. “And that’s where we are.”

Johnson’s committee was established by the town council and had its first meeting in February. Since then, the committee has been soliciting input from residents, business and community leaders, and presented a proposal to council in April, which was forwarded to the SCDOT.

His committee drafted a “guiding principles” doctrine that is the core for reasonable alternatives to the project. They are:

• Fix the transportation issues in the corridor in a way that improves the safety and quality of life for all residents, workers and visitors to Hilton Head Island.

• Improve the safety and quality of life for the residents of the neighborhoods and businesses directly impacted by the U.S. 278 corridor.

• Have a gateway to and from Hilton Head Island that the region will be proud of.

By all accounts, the bolts and nuts work will begin for everyone after the Sept. 19 meeting.

“After Sept. 19, our work really begins as a community and as a committee,” Johnson said. “We have to dig in [and discover] what are the tradeoffs between these alternatives.”

All agencies, governments and committees involved will solicit feedback on the best alternative solution to the myriad of issues.

The town committee expects to submit its recommendations to council by January or February, Johnson said.

The SCDOT will present its final “least impact” recommendation in the fall 2020, Winn said. Then, the federal government will commence environmental analysis, local right-of-way acquisition and a construction timetable by the state.

Winn said construction is expected to begin in 2023-24 with a three- to four-year completion window.

Lowcountry resident Dean Rowland is a veteran senior editor and freelance writer.