§ Chris Grayling
To ask the Secretary of State for Transport what his policy is on maximum noise levels from straight-through car exhausts on customised cars. 
§ Mr. Jamieson
Only new cars are subject to maximum noise limits. However, Regulation 54 of the Road Vehicles (Construction and Use) Regulations 1986 does set minimum requirements for the maintenance of exhaust systems and silencers for cars, and other vehicles, in use. This requires that they be fitted with a silencer, that the silencer is maintained in good and efficient working order and has not been altered so as to increase noise. The Regulations also make it an offence to use a car in such a manner as to cause excessive noise that could have been avoided by the exercise of reasonable care on the part of the driver. It is likely that a straight-through exhaust, whether used on a customised car or any other vehicle, would be in breach of this requirement. Enforcement, however, is a matter for the police.