It is a requirement for the registration and entry into service of new motor vehicles in the European Union that they have type-approval in accordance with directive 70/157/EEC as amended by directive 1999/101/EC, which sets down the permissible sound levels and exhaust systems for motor vehicles. Vehicle in-service standards are specified in the Road Traffic (Construction, Equipment and Use of Vehicles) Regulations 1963 which requires vehicles to be fitted with a silencer or other device that is suitable and sufficient for reducing to a reasonable level the noise caused by the escape of exhaust gases from the engine. An examination of the silencer to assess its effectiveness in reducing noise is part of the NCT and the roadworthiness test carried out on commercial vehicles. It is an offence to use in a public place a vehicle which causes excessive noise. Enforcement of the law in this regard is a matter for the Garda Síochána.