Hong Kong develops AI system to identify illegally modified vehicles
Hong Kong's Environmental Protection Department is developing an AI system to detect illegally modified vehicles by analysing noise. The system is still in development and testing. Authorities have shared data on noise complaints and enforcement actions from the past three years.
Hong Kong — The government is developing an artificial-intelligence system to identify illegally modified vehicles by their noise, the Environmental Protection Department (EPD) has confirmed.
In a legislative council reply on 4 November 2026, the EPD said its "AI-modified vehicle identification system" uses microphones, infrared cameras and tablet computers to convert the sound of passing vehicles into acoustic images. An AI model then compares these images against a database to flag vehicles with suspected illegally modified exhaust pipes.
The system remains at the technical development stage, the EPD said. It is undergoing model training, function adjustments and field trials, particularly to improve its ability to detect concealed modified exhaust pipes at night. The EPD has referred suspected cases found during trials to enforcement authorities.
Data released by the Transport Department and the EPD show that in the past three years, they received 3,522, 3,891 and 4,105 noise complaints about vehicles respectively. Among these, 1,200, 1,450 and 1,600 were reported as involving illegally modified cars. Inspection orders were issued in 450, 520 and 600 cases. The police said they do not keep separate records of related complaints and prosecutions.
The EPD said it has collected sound data at suspected hotspots where illegally modified vehicles gather, including areas known for illegal racing. The system is designed to analyse acoustic features of vehicles to help enforcement. The EPD is working with the Transport Department and the police to refine the technology and strengthen reporting mechanisms.
Under the Road Traffic Ordinance, all vehicles must meet noise standards. Police can order a suspected illegally modified vehicle to an inspection centre. The Transport Department can cancel a vehicle's licence if the owner fails to comply with an inspection order or if the vehicle fails the test.