Traffic relief for Mount Pleasant

Traffic back-ups such as this one Wednesday evening, coming off the Arthur Ravenel Jr. Bridge, is what Mount Pleasant is looking to avoid with its road-widening and a new traffic-light system.

MOUNT PLEASANT -- Dental hygienist Amy Natoli lost her good cheer Monday night during the commute home on U.S. Highway 17 when she sat through a light changing four times.

"I was crazed," she said.

She moved here from the New York City area.

"I might as well be on Long Island again," Natoli said she thought.

Natoli said it's common for afternoon rush-hour traffic to get backed up on the Arthur Ravenel Jr. Bridge during the drive to her house near the Towne Centre.

Some relief is on the way for Natoli and other commuters in the form of a high-tech traffic-light system designed to keep the cars moving more smoothly. The Town Council Bids and Purchases Committee on Wednesday agreed to buy the new technology.

"It's cutting-edge," said Brad Morrison, director of the town Transportation Department.

Mount Pleasant will be the first community in the state to have the new traffic-light system, which has proven its worth in a trial run on U.S. 17 from the Wando Crossing shopping center to the Isle of Palms connector, where travel time was reduced by 30 percent, Morrison said.

The committee voted to spend $436,000 to include installation of the InSync Adaptive Traffic Control System for stoplights on about five miles of U.S. 17 from the connector to near Wando High School.

Some 25 percent less fuel consumption is another documented advantage of the system, said Mayor Billy Swails. "We certainly want to make the traffic move better," he said.

The traffic-light change will happen by this fall at eight intersections on U.S. 17 from the connector going north.

A few months later, the $84 million widening of the road from the Ravenel Bridge to Interstate 526 is expected to be finished. As part of that project, U.S. 17 will rise as an overpass at Bowman Road.

Charleston County is supervising the road-widening construction from the Ravenel Bridge to I-526. In a separate project, the town is in charge of widening U.S. 17 to six lanes from the IOP connector to near Wando High School.

Rhythm Engineering manufactures the new traffic-light control system, which the company said reduces stop-and-go driving up to 90 percent. Exhaust emissions are cut by 30 percent, it said.

The company said InSync uses digital sensors that know the exact number of cars waiting in each lane and how long they have been there. The information is fed up the line of traffic lights to keep cars and trucks flowing as smoothly as possible.

"The plan is that once you get off the Ravenel Bridge you can drive all the way to Wando High School without stopping," said Councilman Elton Carrier.

The technology adapts second-by-second to changing traffic and manages the lights accordingly. It uses data collected from cameras and through coils buried at intersections and attempts to move cars along the road with no stops.

In Charleston, traffic is managed in a different way, said Hernan Pena, director of the city Department of Transportation.

Timing of traffic lights has been configured based on a study that accurately projects traffic flow depending on time of day, he said.

"The patterns are predictable," Pena said.

The results have been fewer stops and delays and greater travel speed, he said.

Although the light timing is programmed automatically based on study data, it can be adjusted manually as needed depending on conditions, he said.