So I walked that street _everyday_ when I was in elementary/middle/high school! My family lives within 3 blocks from there. The one you refer to specifically is a really walkable neighborhood one, I'd guesstimate 95-99% of the people who buy there go/leave walking. Spanish people living in cities/towns don't take the car for grocery shopping, in fact we do make fun of US that need to take the car for that! Only if you live in the outskirts of the city/town/countryside you'd take the car for shopping.

Note: given the area of that one, I'd also guesstimate the vast majority of the people parking in that Mercadona were JUST using it as a random short-term parking, not as the supermarket parking! Like if you go to the area you park there, then do your business/visit your friend/whatever, then maybe buy a couple of things in Mercadona so the parking is free (and you probably needed those things for the week anyway). At least that's how locals would use that parking, because: if you live within 3-4 blocks you'd walk, if you live further than 4 blocks you'd go to another Mercadona that is within 3 blocks of your home, and if you live very far away you'd drive to a larger supermarket on the outskirts, not to this small one in the city center (except, as I said, if you have other business to attend there and then you use the parking as a convenience, and buy something for free parking).

> we do make fun of US that need to take the car for that! Only if you live in the outskirts of the city/town/countryside you'd take the car for shopping.

This seems similar to the situation in the US, with the major difference that far more people in Spain live in a central area rather than in the outskirts. The distinction to make fun of is not how people in cities in either country live, but the large numbers that live in the outskirts/suburbs in the US.

When I've been to the US, a very very large part of the population would live in what I'd call "outskirts" in Spain/Europe, meaning low-density residential areas where it's not feasible to have a supermarket every other block. Not only most of entire cities like L.A., but this would include most of San Francisco like the whole west area (Richmond+Sunset?) and many others (Japan town, the piers, etc). Like the middle class, USA cities also seem to be missing "middle buildings", the bulk of which constitute European cities. 4-10 floors building blocks are what make most of Valencia, Barcelona, Madrid, etc.

Yes, exactly. San Francisco has a higher population density than most larger European cities (London, Madrid, or just Valencia) but the "outskirt parts" of the city seem more evenly spread out, whereas its European counterparts tend to maintain the more agglomerated village-style development throughout their outskirts. This style of undeveloped areas interspersed with denser neighborhoods, found in central areas in SF and larger European cities (but not as much in non-central areas of SF) tends to be far more effective for other urban factors such as public transport.

It's easy to underestimate how inefficient car parking is. On a street that dense there's no way more than 5-10% of residents own cars, there just wouldn't be room for them.