Shortly after 5a.m. on a cold day in January, a crowd outside a club near 10th and Chestnut streets began to get unruly, pushing, shoving, and yelling. Then a driver in a parked car backed it quickly, ramming another car full of people. More yelling, more pushing, more shoving – until two gunshots were fired as a warning, their flashes lighting up the darkness. Five seconds later, police arrived and the crowd dispersed before more shots were fired.

How did police get there so fast? The disturbance had been caught on one of the 19 new security cameras city police installed last year. The cameras’ images were being monitored by civilians in a City Hall room full of big-screen televisions, computers, and joysticks.

Worried about the growing tumult, the civilians had radioed police a minute before the shots, suggesting they might want to calm the situation. The system worked. This second round of 19 security cameras, like the first round of 27 cameras, was bought with a federal grant. The entire system now costs a bit more than $300,000 a year to run, the equivalent of three police officers. Police Chief William M. Heim said it’s worth it.

"They don’t replace cops," he said of the cameras. "But their eyes are on the street in 46 places and record 24/7." The city police force has been cut about 20 percent from five years ago. The camera network "provides eyes in all these sections where we can’t have officers," said Sgt. Stephen Anderson, in charge of City Hall’s Video Safety Unit.[…]