Amsterdam has started using electric road signs to warn drivers if their vehicles are too loud, with plans to replace these signs with 'noise cameras' that can automatically issue fines. The city is conducting an experiment to reduce noise nuisance from motorcycles and cars. The noise cameras use microphones to detect loud vehicles and take photos of license plates to issue fines. The technology is being tested in several locations in Amsterdam and may be certified for use in other cities if the experiment is successful.