diàn​zǐ​jǐng​chá

police surveillance

电子警察 (電子警察) diàn​zǐ​jǐng​chá
police surveillance
electronic monitoring or closed-circuit television system used by law enforcement for public security and crime prevention
traffic camera
automated electronic system used for detecting and recording traffic violations such as speeding or running red lights

Sources

Definitions
CC-CEDICT