The stats sound about right, based on general world experience.

What those don't address is quantity per category. There's way more cars than motorbikes on the roads (in Switzerland and most EU/North America areas).

The loudest part of a car is usually (assuming it's got a legal muffler) the wheels in contact while rolling at speed. So, while few cars might be breaking a sound law individually, the sheer quantity of cars driving fast makes for the general cacophony you hear in the city. It's then punctuated with motorbikes, car horns, and leaf blowers. That basic rumble you can never escape is just the tires of the cars rolling along.

Also assholes playing loud music. The only reason for that is because you're attention starved. Turn the music down and go get a hug you dicks.