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Motorcycles: Exhaust Emissions

Question for Department for Transport

UIN HL1192, tabled on 17 June 2021

To ask Her Majesty's Government what restrictions exist, if any, on the volume levels of motorcycle exhausts when travelling (1) on dual carriageways, and (2) on roads with a lower speed restriction.

Answered on

30 June 2021

New motorcycles are required to meet strict noise limits in a range of driving conditions before being placed on the market. The current limit within the approval test is between 73 and 77 decibels (dBA) depending on the power to weight ratio of the machine and is not specific to types of roads.

Once on the road, regulations require that exhausts and silencers shall not be altered to increase noise above the level the motorcycle was originally approved to. The police also have powers to take action if they believe excessive vehicle noise could have been avoided through reasonable driver care.

The annual vehicle MOT test requires an inspection of the state of repair of the exhaust and the tester uses their experience to make a subjective assessment of the noise levels. A vehicle should fail the MOT if the silencer has been altered to increase noise above the level expected from a standard system.