Inside a dimly lit Cherry Hill office that resembles a miniature NASA mission control center, technicians move joysticks to swivel cameras on towering utility poles miles away.
In another office in King of Prussia, workers perform the same task, scanning a wall of monitors for a bird's-eye view of traffic backups and accidents.
Across the region, hundreds of overhead cameras - some on 55-foot poles - are watching you.
Often, the images are mundane. But sometimes they involve life-and-death situations beyond car crashes.
Jumpers on the Benjamin Franklin and Platt Bridges in Philadelphia. A motorist claiming to have a bomb on I-676 at the Camden-Gloucester City border. Or a man, intent on suicide, running into traffic at Routes 29 and 129 near Trenton.
When they see something, the state technicians in Traffic Operations Centers in New Jersey and Traffic Control Centers in Pennsylvania alert police and fire departments or send other aid to clear up problems and keep the traffic moving.
They also communicate with motorists through electronic message boards on many major highways, warning about accidents and bottlenecks or issuing Amber Alerts when a child is missing.
The timing of traffic signals can be changed from the centers, too.
"Our goals are clear," said Dennis Motiani, site manager of the New Jersey Department of Transportation's operations center in Cherry Hill. "Our surveillance is for a purpose. We help keep the traffic moving on a daily basis."
In New Jersey, about 160 cameras monitor traffic. Nearly half are in South Jersey, on major roads including Interstates 295, 76, 676, 80 and 287; the New Jersey Turnpike; and Routes 30, 42, 70, 73, 38, 42, 130 and 202.
Cameras in the Route 29 Trenton tunnel set off an alarm in the operations center when a car remains more than a minute without moving.
The Cherry Hill office monitors - but does not record - the traffic flow 24 hours a day, Motiani said. A similar facility in Elmwood Park, Bergen County, keeps track of traffic in the rest of the state.
"We're adding cameras very prudently," said Motiani, whose office added two more on Thursday. "We also have to keep the ones we have maintained."
The cameras are heated in the winter to prevent them from frosting up and can be raised to the sun or lowered to help melt and dislodge the ice.
And when they focus on a problem - such as a disabled vehicle - the Traffic Operations Center dispatches Emergency Service Patrol units to provide assistance. The units patrol from 4 a.m. to 8:30 p.m., fixing flats and providing gas.
"We find out about an incident" by observing it, Motiani said, "or somebody calls it in, and then - if needed - we notify the state police and send an ESP unit. We want to open up highways as soon as possible."
Troopers are often needed to help clear up problems, said State Police Lt. James Sullivan, who heads the Incident Management Unit at the Traffic Operations Center in Cherry Hill.
Sullivan has framed plans to alleviate congestion - sometimes for special events, including parades and walks that use major roads.
He said he was in Hamilton in May when he received a call about a motorist who stopped on I-676 near the Camden-Gloucester City border and claimed to have a bomb.
While technicians in Cherry Hill watched, an ESP driver checked on the vehicle, then backed off after hearing of a bomb and notified authorities, said Sullivan, who helped investigate the incident. The claim was false, and the man was arrested.
The traffic cameras also captured images of a man who tried to kill himself in January by driving into an abutment at Routes 29 and 129 near Trenton but missed and went down a hill toward railroad tracks, Sullivan said.
The man drove onto the tracks, seeking to be struck by a train, then ran into traffic, where he was hit by a car and fatally injured by a tractor trailer.
In Pennsylvania's five-county Philadelphia area, where 103 closed-circuit cameras scan traffic on many major highways, state Department of Transportation traffic control technicians have seen similar incidents.