Another bridge? Rush-hour lanes? 5 things to know about US 278’s future on Hilton Head
Can Hilton Head Island’s traffic problems be solved by another bridge to the island?
How about lane reversals at rush hour?
The answers to these questions are part of a newly released report by an engineering firm reviewing the S.C. Department of Transportation’s plans for Hilton Head’s bridges and U.S. 278.
The firm hired by the Town of Hilton Head Island and Beaufort County, HDR Engineering, was tasked with looking for new alternatives and reviewing SCDOT’s plans for the corridor. The agency hopes to present its plan to the public in July.
But with all the differing ideas for the bridges and the way widening threatens the historic Stoney community, the report reads like a catch-all for questions posed by area leaders and residents.
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Some have looked to the $134,732 engineering review as a referendum on the process used by SCDOT, which has been charging forward with plans for the $300 million construction project. It will shape the final alternative for the bridge, although at least one town council member said the report “smells more like a peer review” than a challenge to the SCDOT.
Here are five things to know about the report and how the plan for the U.S. 278 corridor may change now that it’s out:
1. Hilton Head’s U.S. 278 will have to be 6 lanes
In its report, HDR engineers wrote that when they ran traffic simulations, the existing four lanes of U.S. 278 backed up beyond the limits of the model.
That pointed to an obvious need for more lanes, the report said.
“The six-lane concept was found to have potential queues at some points along the corridor, but all queueing was maintained within the model network,” the report says.
That’s a scientific conclusion for a highly emotional issue.
Adding another lane of pavement on the highway would bring the roar of traffic closer to homes that belong to native islanders like Isabelle Stewart and Belinda Stewart Young, whose families have been living in Stoney for generations.
Young, whose mother is 92 and lives off U.S. 278, told The Island Packet in 2019 that her family’s mailbox had been taken out by drivers so many times they finally moved it back from the road.
Another lane of pavement would make the highway so close that cars would splash water onto their home’s porch on rainy days.
2. There isn’t a plan for a second bridge or lane reversals
Phillip Hutcherson of HDR said his firm looked at ideas from islanders to create a second bridge that connects the Cross Island Parkway to Bluffton or Beach City Road to St. Helena Island.
The upshot is that those options are too expensive.
HDR devotes just a over a page in its 20-page report to these ideas.
“Adding a different entrance to Hilton Head would need to be a different study or analysis,” Hutcherson said Monday. “We looked at it from a very high level, but that is really a different project.”
Ward 1 representative Alex Brown challenged the report’s dismissal of such ideas.
“To the general public, this is going to smell like a peer review more than anything else, and that’s not what we signed up for,” he said.
Adding a new bridge would cost between $450 million and $800 million, depending on the location, the report said.
Traffic reversals that would give extra lanes to rush-hour traffic were also taken out of the equation, the report said, because vehicles need to turn in and out of the corridor. That is made more difficult if there are reversible lanes.
3. Hilton Head bridge’s speed limit should change
Instead of the 55 mph speed limit on the bridges, Hutcherson said his firm recommends the speed limit of the entire corridor from Moss Creek to the Cross Island Parkway be lowered to 45 mph.
4. Car crashes make it a dangerous corridor
HDR’s report found that there were 797 crashes along the corridor in just 5 1/2 years from January 2013 to June 2018.
The corridor has about the same percentage of severe crashes as the statewide average. Across South Carolina, around 24% of crashes involve either an injury or fatality.
These numbers are made much more real in the wake of a Saturday morning crash on the westbound Hilton Head bridges, where three young people died after a collision caused a pickup truck to go over the Mackay’s Creek bridge.
The existing cement barriers on the Hilton Head bridges are 32 inches tall, according to SCDOT spokesperson Ted Creech. When the corridor is redone, the barriers will be raised to the federally-mandated standard of 42 inches tall.
Hutcherson said a majority of crashes aren’t like Saturday’s: They are rear-end crashes caused by congestion, as well as intersection crashes. To mitigate those problems, his firm suggested a traffic light timing cycle where traffic on U.S. 278 has a green light 90% of the time.
His firm also suggested alternative intersections that reduce potential collision points from 32 conflict points in a normal four-way intersection to 18 conflict points in a staggered intersection.
5. SCDOT needs to share more information
Hutcherson said Monday that the firm found that the public is missing key information that would help residents better understand the project.
He said SCDOT should release detailed cost estimates for each of the nine reasonable alternatives, a description of each intersection and how it is serving drivers, as well as a travel time analysis for the corridor.
This story was originally published May 3, 2021 at 2:33 PM.
