You really notice it too, walking around the city feels very quiet even though there are so many people and a decent amount of noise from businesses. When you make it to a busy road, there's a notable lack of businesses nearby and you really notice the noise difference. That said, car speeds in Japanese cities are slow, and cars are heavily regulated so they're just not as loud as other cities.

Cars add a sort of tense background track to life, perhaps because we perceive the danger subconsciously as a pedestrian. Sitting in my house in the burbs I can hear the highway out the window, in Tokyo, Osaka, Kyoto, there was a type of quiet I just wasn't expecting from a city.

I think the enabling features for this to occur are of course public transport and mixed use streets, mixed use sets the stage for a sensible compromise between cars and people. The majority of streets do actually allow cars, but you barely see any using them because they'd be incredibly slow, like walking speed. This means that if you decide to use one, you must really need it and so you can, but if not then you'll just use a road more suited to fast cars.