The four black cameras perched high above a silver pole at the intersection of U.S. 278 and Buck Island Road in Bluffton appeared seemingly out of nowhere.
Turns out, the devices were installed seven months ago by S.C. Department of Transportation contractors. And they aren't even really cameras -- at least not the way most think of the word.
"These are video-detection cameras for the traffic signal. They do not record video, only provide vehicle detection for the traffic signal operation," according to Pete Poore, a DOT spokesman.
Most intersections on U.S. 278 are controlled by wires installed in the asphalt that are "tripped" when cars approach a red light. Poore said the wire system was removed at this intersection during the $23 million U.S. 278 widening project.
Cameras perform a function similar to the wires. Once they detect cars lining up at the intersection, a process begins that determines when the traffic light will change.
Colin Kinton, Beaufort County's traffic engineer, said at least four other intersections in the county are managed by traffic-control cameras. Those systems are preferred because wires installed in the pavement are occasionally severed by utility crews, disrupting traffic and requiring a costly fix.
"Video-detection cameras provide us with another tool in the tool box in order to keep up with traffic flows and keep traffic moving," he said in an email. "We can quickly make adjustments with them from our offices without closing travel lanes and placing employees and motorists at increased risk."
Traffic-control cameras also are installed along U.S. 278 at intersections with Simmonsville Road, Rose Hill Plantation, Buckwalter and S.C. 46.
The county asked the state to install the cameras and the county also has responsibility for maintaining them. Kinton says the cameras will remain in place after the widening is finished.
More cameras will be installed as state funding is available.
Meanwhile, the county is planning to install a traffic-monitoring camera at the Buck Island/U.S. 278 intersection soon, replacing one near Rose Hill Plantation.
All told, nearly 80 traffic cameras have been installed at nearly three dozen sites throughout Beaufort County, although most are on U.S. 278 and S.C. 170. Residents can monitor activity on the roads through those at islandpacket.com/traffic .
Follow reporter Casey Conley at twitter.com/IPBG_Casey.