The requirements might be based on what’s achievable with reasonable efforts. Intuitively, I would think motorcycles are louder, but I may just be wrong (they a

The requirements might be based on what’s achievable with reasonable efforts. Intuitively, I would think motorcycles are louder, but I may just be wrong (they are smaller and do less work, after all). This logic may seem strange but it isn’t unusual. Some jurisdictions have different fuel efficiency and pollution standards for diesel/gas vehicles or different sizes for example. In those cases, it’s the only way to improve without abolishing the less efficient classes outright. Alternatively, one could reason that motorcycles are used recreationally more often than cars, and that such activities have less legitimacy to annoy people.