DfT wants to police bike exhausts. It has no evidence

The Department for Transport wants to bring motorcycles, scooters and mopeds into an emissions law that has never applied to them. If it goes ahead, a rider in Great Britain whose bike no longer meets the emissions standard it was built to, because of a de-cat pipe or an engine remap, say, could face a fine of £1,000 or more. There's one awkward detail. Asked in writing for the evidence behind the change, the DfT said it didn't have any.

This information is not held; the Department holds no analysis or evidence of this kind that was relied upon in developing the proposal.
— Department for Transport, responding to an information request from the Motorcycle Action Group

What the DfT is proposing

The change sits in a consultation called "Regulating environmental impact of in-use emissions of road vehicles", which ran from 6 July to 6 September. It concerns Regulation 61A of the Road Vehicles (Construction and Use) Regulations 1986, a rule that says vehicles must keep meeting the emissions standards that applied when they were built.

At the moment it only covers cars and vans up to the Euro 4 standard, and lorries and buses up to Euro V. The DfT wants to extend it to newer vehicles and, for the first time, to what it calls category L. In its own words: "Regulation 61A has never applied to any category L vehicle (mopeds, scooters, motorcycles, tricycles and quadricycles)." The proposal covers vehicles from 1 January 2001 onwards, and it includes changes made "whether to hardware or through alteration to software", so remaps count as well as pipes.

Enforcement would use existing Road Traffic Act offences, with "fines of between £1000 and an unlimited amount following successful prosecution in the magistrates' court." The DfT hopes to legislate in summer 2027, with six months' notice before enforcement starts. It applies in Great Britain; Northern Ireland has its own separate rules.

The evidence that isn't there

The Motorcycle Action Group, a riders' campaign group, used the Environmental Information Regulations to ask the DfT what it had relied on. The answers, which MAG has published, are strikingly frank. The department said it holds no analysis attributing excess emissions to "poor maintenance or deliberate modification/tampering", no comparison of tampering between older and newer vehicles, and no assessment of the data it was asked about.

The consultation itself explains motorcycles' inclusion this way: "given that they have the potential to contribute to excess emissions when in-use we have not identified any clear policy or technical reasons to exclude them from the scope."

MAG's director, Colin Brown, was not impressed. "Its own consultation says motorcycles are included because officials had 'not identified any clear policy or technical reasons to exclude' them; that is not evidence, it's a shrug," he said. "Riders deserve better than being brought into a new criminal offence on a shrug."

Why it matters to British riders

Aftermarket exhausts are a huge part of motorcycling culture, and plenty of riders have fitted one without thinking of it as tampering. Under the proposal, what matters isn't whether a part is aftermarket but whether it makes the bike exceed its original limits. That's a technical question most owners have no way of answering in their garage, and the DfT admits that "the scope of what can be assessed" at an MOT is limited.

MAG also points to Transport for London's own testing, which it says shows "around 97% of motorcycles, mopeds and scooters entering the London Ultra Low Emission Zone already comply with its standard". Motorcycles.News, citing industry figures, puts bikes at about 1% of UK traffic and 0.4% of domestic transport emissions. On those numbers, it's hard to see bikes as the heart of the problem.

To be fair to the DfT

The underlying idea is reasonable. A vehicle should stay as clean as it was when it was sold, and it's odd that cars must and motorbikes needn't. The DfT says plainly: "We are not seeking to prohibit all vehicle modifications." It also says its enforcement focus "will likely be upstream", meaning the businesses selling illegal modifications rather than individual riders at the roadside. Removing a catalytic converter is removing a catalytic converter, whatever it's bolted to. Including every vehicle type also avoids creating a loophole. But a consistent rule still needs a reason, and a consultation is the place to give one.

Mind the hype. Loud pipes might save lives. On this evidence, they won't save the DfT's homework.

Sources: GOV.UK (DfT consultation), Motorcycle Action Group, Visordown, Motorcycles.News