Abstract: Off-site law enforcement comes is an important means for investigations into unlawful acts of motor vehicles. The metrological performance of monitoring devices, however, directly affects the accuracy and impartiality of law enforcement. By collating the monitoring equipment used by traffic police, environmental protection, and traffic competent authorities for off-site enforcement of motor vehicles and their metrological specifications, the characteristics of the monitoring equipment for off-site enforcement of motor vehicles and the existing verification and calibration methods are sorted out and analyzed, and the monitoring system for motor vehicle honking is used as an example to make recommendations on the verification and calibration methods for monitoring equipment.