You can make good arguments that motorcyclists should not be exempt for paying their fare share. But their proposals are punitive, not fair, and they are admitting it.
What do sound levels have to do with parking? There are legal restrictions on noise levels, if any vehicle is exceeding those then there are legal remedies. Excessive charging for parking does nothing to address the problem. It penalizes those who are acting legally. And most notably, parked vehicles do not make any noise.
And making claims “relative to their share of traffic” is blatantly corrupt. Accidents are absolute, not relative. Collisions occur with real vehicles on the roads, not extrapolated ones that do not exist.
But even then, I would still like to see evidence for that uncited claim because it does not sound right.
The most recent government data I can find, unsurprisingly, puts the percentage of injury to cyclists and pedestrians from motorcycles as the lowest for all motor vehicles. Even an outright ban on motorcycles would make a negligible impact on safety to those categories. And more likely would lead to many of those motorcyclists switching to statistically more dangerous cars
Sources: Road safety factsheets and ad-hoc statistics - GOV.UK
Their proposal for the cost of a resident’s permit for a petrol motorcycle is for it to be exactly the same as for a petrol car (up to 120 g/Km CO2), despite a vastly different road space requirement and that almost all the bikes which you would risk leaving parked on a road having much lower emissions.
They are charging the same of a kid with a Chinese 125cc scooter as a family with a Citroen Grand C4 Space Tourer. (I know nothing about cars, I looked it up and that one look big and only 105 g/Km CO2)
They say their stated intention to “discourage inessential motorcycle journeys,” yet are essentially doubling the cost of residents permits despite that having no baring on a journey type.
Meanwhile, after two years their intention is to scrap the £6 daily parking charge and have petrol motorcycles charged the same as petrol cars. But before then, if these proposals are adopted, if you only want to quickly stop somewhere for an hour it will be £3.43 in the north of the borough or £4.31 north of the inner ring road in a petrol car, compared to a flat £6 for using a motorcycle bay in the same street.
I do not like live in Camden and am unlikely to ever need to park there, but if I did I would park parallel to the kerb to get my monies worth. If they want to charge you for the road space of a car, make sure you use the road space of a car and not let them charge you four times as much, relative to the share of road space of a car.
This is not simply closing a “loophole” of motorcyclists not paying anything, there is no fairness or proportionality in their proposals.