NEW YORK CITY (PIX11) – The city’s new gun-detecting scanners set up at some subway stations produced false positives on over 4% of scans, according to the NYPD. The city tested the machines, which look like traditional metal detectors, at 20 subway stations for 30 days. In that period, the machines produced 118 false positives of 2,749 total scans, a false positive rate of about 4.3%, according to police.