> Where I live in Los Angeles, a very large number of people park their cars primarily or exclusively on the street.

> Such a change would have a significant impact.

What would that impact be? Do you see, or experience, a lot of contention for nighttime parking?

There's plenty of contention for street parking in nonresidential areas. But a nighttime parking certificate doesn't do anything about that. Nighttime parking is done in residential areas.

It's not like you have to get waivers to park your cars in front of your house in Japan. Your car MUST have a designated lot, with proofs(more or less a set of simple declaration forms than anything detailed and concrete), to be registered under your name. Otherwise it cannot be registered. A full waiver for parking violations technically exist, but they are reserved for official and/or actually special vehicles only(like actual fire trucks). The vast majority of cars stay in an off-of-road parking lot of some sort, be it a fancy mechanical one or a crude gravel lot next to apartment complex.

I reckon that not many other country do that kind of legal setup. But Japan is among those very few.

Not the person you're replying to, but I see the same thing happen in the Capitol Hill neighborhood of Seattle. Dense neighborhood with a lot of nightlife, but many of its residents exclusively use free street parking to park overnight. There is a lot of contention for spots after about 7pm.