The President of the AA has warned UK drivers that modifying a car exhaust to make it louder could lead to failing their MOT test. Edmund King, President of the AA, said that such modifications could backfire, as mechanics are likely to identify the issue during the annual test.
MOT Testers' Discretion on Exhaust Noise
The MOT test does not have a specific decibel limit for exhaust noise, and vehicles are not measured with a dedicated tool. Instead, testers are allowed to fail models they consider a "nuisance" on the road. The MOT inspection manual instructs examiners that exhaust noise "must not be unreasonably above the noise level you'd expect from a similar vehicle with a standard silencer".
Examiners could even issue a 'Major' fail, meaning the vehicle will not pass the test and will be off the road when the previous certificate expires. Speaking exclusively to the Express, Edmund warned that "deliberately modifying" a vehicle's exhaust could come back to bite.
Legal Limits and Public Support for Crackdown
He said: "There is a difference between enjoying the sound of your car and deliberately modifying an exhaust to make excessive noise. It is illegal to modify an exhaust system to make a vehicle noisier than when it was type-approved, and excessively noisy vehicles can also fail the MOT."
Edmund added: "Modifications need to be legal and safe, and drivers need to remember that they share the road – and neighbourhoods – with everyone else."
Brand new cars are now required to meet UNECE noise limits, which have been progressively reduced over the past half a century. New cars used to have a maximum of 82 decibels in 1978, but the current limit is set at 70dB.
Driving with an excessively loud exhaust is also likely to annoy other motorists. A previous survey from the RAC found that almost six-in-ten drivers (58%) would support the introduction of 'noise cameras'. These would be fitted with a range of microphones, looking for vehicles that exceed the type approval noise limit. Trials of the equipment have already been held in major cities such as Bradford, Bristol, Great Yarmouth and Birmingham.
