On 28 October, the EPA held a public demonstration to exhibit the accuracy and impartiality of the acoustic camera systems in front of the media and automotive enthusiast groups. The EPA stresses that unmodified cars, limited edition cars, sports cars with high horsepower, and cars or motorcycles modified with certified exhaust systems will not surpass the noise threshold easily without inappropriate driving behaviors such as engine revving.
The EPA is in the process of amending the Motor Vehicle Noise Control Standards and the In-use Motor Vehicle Noise Control Regulations to include regulations on the use of acoustic cameras. During the past two discussion meetings for the amendments, some car enthusiasts and clubs expressed their concerns regarding the accuracy and impartiality of the acoustic camera systems and the noise disturbance from the surrounding environment. To ease their concerns, the EPA held a public demonstration at a national laboratory for noise regulations to show how an acoustic camera system is approved, how background noise is corrected for, and how loud vehicles are discerned. In addition, the EPA also demonstrated that the monitoring results acquired by the acoustic camera systems are no different from those acquired by using the existing method of manually operated microphones.
An acoustic camera system consists of a variety of equipment including microphones for noise detection, an anemometer for correcting for the environmental disturbances such as wind resistance, a fisheye camera that records the surrounding environment of the camera location within three seconds before and after the noise nuisance is detected, a license plate recognition system, and a control unit. The EPA states that the new monitoring system will be strictly calibrated and triply approved to ensure its accuracy and impartiality.
1. Verification approval: the sound level meters used in acoustic camera systems must meet the qualifications of a sound level meter for official inspection and testing (Class 1) in compliance with the Weights and Measures Act. In addition, the meters have to be verified by the Bureau of Standards, Metrology and Inspection of the Ministry of Economic Affairs every two years.
2. Comparison testing: the acoustic camera systems must go through comparison tests conducted by EPA-approved noise labs once a year based on the Noise Measuring Methods for In-Use Motor Vehicles – Image-Assisted Method (NIEA P211.80B) announced by the National Institute of Environmental Analysis.
3. Strict Calibration: when an acoustic camera system is in use for law enforcement, it shall be calibrated using the sound calibrator approved by the National Measurement Laboratory once every three days. The system shall also be adjusted according to the national standard time every five minutes.
During the demonstration, the EPA conducted comparisons among unmodified motorcycles, modified motorcycles with certified parts, modified motorcycles with uncertified exhaust systems, and unmodified limited-edition sports cars as they accelerate to 50 km/h, 60 km/h and 70 km/h. The demonstration showed that inappropriate driving behaviors and illegally modified vehicles exceeded the limits of the noise standards, while unmodified or legally modified vehicles easily passed the test. The vehicles modified with the certified exhaust pipes of the quality brand “Akrapovič” also passed the test.
When an acoustic camera system detects noise that exceeds the limits, it will be confirmed as a violation after adjusting for the background noise and eliminating the environmental disturbance within three seconds before and after the detection, if there is no rain at the moment of detection and wind speed is lower than 5 m/s. Any violations will be subject to a fine of NT$1,800 to NT$3,600 in accordance with Article 26 of the Noise Control Act. If illegally modified vehicles with uncertified exhaust pipes are noticed in the pictures taken by the cameras, violators are to go through in-person inspections and make improvements within a prescribed time frame in compliance with the requests from local environmental protection bureaus.
Excerpt from Environmental Policy Monthly, 23 (11)
- Environmental Protection Administration, R.O.C.(Taiwan)