More than 70,000 cars cross the Wando River bridge on Interstate 526 during an average weekday — much of them during rush hours.
They use four lanes.
On Monday, they were crammed into two lanes as a single side of the bridge was open to two-way traffic for the first time during rush hour.
With the change, eastbound commuters got a taste of the gridlock that has stalled motorists driving from East Cooper to Charleston over the past week, extending some of their journeys by 40 minutes.
But the reversal of one eastbound lane on the James B. Edwards Bridge alleviated the hours-long travel times some had seen after the westbound side of the twin spans closed May 14.
"I don't think anybody's enjoying this," Traffic Engineering Director Rob Perry of the S.C. Department of Transportation said as traffic flowed in two directions over the bridge behind him. "We're trying to see what's the best fit ... to get everybody to and from their work. ... From a traffic standpoint, this is the best fit."
While the measure delayed some people driving from North Charleston to Daniel Island and Mount Pleasant, DOT Secretary Christy Hall said it worked "as expected." And the added commute time, Perry added, dropped from 40 minutes during the morning rush hour to 15 minutes during most of Monday.
Speeds on eastbound Interstate 26, a typically clogged artery between Summerville and Charleston, ranged from 16 mph to 30 mph during peak travel times, DOT data showed.
Officials said they anticipated slowdowns during the first few days of crossover traffic on I-526, but the traffic flow was an overall improvement to the headaches that had some commuters taking boats to work.
Few jams were reported on the westbound side of I-526, except for a section where the lanes are cut from two to one near Long Point Road.
But eastbound cars were bumper to bumper for more than 5 miles during the height of Monday morning's rush hour, clogging I-526 between the bridge and North Rhett Avenue in North Charleston.
Mount Pleasant Mayor Will Haynie watched the traffic from a command center as DOT counters reported about 1,300 cars per hour Monday morning crossing the bridge in each direction.
"I think we’ll see it even out more," he said. "All in all, I think it’s a plus."
But some detractors who got tied up in the traffic took to social media and vented their frustrations.
"This is a commute that was previously unaffected by the Wando bridge issues," said one Twitter user, who reported a 45-minute, 4-mile slog. "How is this helping?"
The discovery of a broken cable that helps tie the westbound span together prompted authorities to close that side of the bridge for emergency repair work. The eastbound side was not affected.
Experts still have not determined the cause of the break in one of eight main lines, though they said corrosion had eaten away at other cables near the same spot.
Contractors during the weekend started feeding various equipment pieces into the bridge's hollow interior, where new cables will be assembled over the coming weeks. Officials have promised to reopen the span June 11.
Other crews, meanwhile, finished paving links allowing westbound traffic to enter an opposing lane on the Mount Pleasant side of the river, then return after crossing the bridge. Some local officials had expressed safety concerns about the effort before Gov. Henry McMaster's directive late last week hastened the DOT's work to put the crossover lanes into place.
The DOT started the new pattern Sunday afternoon.
No wrecks were caused by the shift overnight Sunday, Perry said, but police officers stopped several cars speeding through the 45-mph work zone.
Cars had choked southbound U.S. Highway 17 from Mount Pleasant to Charleston last week in the opening days of the shutdown, but motorists reported normal commute times Monday. The other of two detour routes available last week, S.C. Highway 41 to Clements Ferry Road, also was improved, Perry said.
"It's by far better than it was last week," Haynie said. "If I look solely at Mount Pleasant, Mount Pleasant is doing fine now. But we are concerned about Daniel Island traffic trying to get back this way."
Some small roads also saw problems Monday because of the eastbound congestion.
Traffic was heavy at Daniel Island Drive and Fairchild Street on Daniel Island, prompting an officer to direct traffic at the intersection until it thinned out about 9:15 a.m., Charleston police spokesman Charles Francis said.
Perry said he envisioned the kinks to be ironed out in the coming days.
"We're going to continuously make improvements," he said. "The first couple of days is usually when you see ... the slower travel times. Folks are still trying to figure out their best way to go from Point A to Point B."