In Los Angeles there are ~ 3 parking spaces per car, and < 1 housing unit per person. We mandate a bunch of parking for every new building, but no housing. Its no wonder that people live in cars.
Any car being used will need >1 space at all times: one at home and one wherever it's being parked when its driver has gone somewhere.
If you have <=1 space per car, the car is either being unused or it's parking illegally sometimes.
We need far more parking spaces per car in LA once we consider the millions of people who are driving in the city and live outside of it.
As far as housing, we'd have a 100% fully housed population with <1 house per person because a large percentage of people live with one or more people.
Actually, those numbers are a problem on their face. They're an illustration of why cars, and societies that are structured around enabling automobile transit as the primary (or even sole) means of transit, are inherently unsustainable and inefficient.
Note that the above is about land area. Housing units are often stacked vertically, while car parking rarely stacked.
Where it is not stacked, it’s obviously not that terribly valuable.
Of course places where stacked parking is even a thought are also places where density is high enough that it isn't hard to run a great transit system and so there is less need for parking at all.
And that doesn't cover opportunity cost or the knock-on effects of market distortion, or the exponentially higher costs of e.g. parking garages.
This is nearing the square footage of an apartment to house the same number of people. So for any given unit of housing real estate we need an equivalent or greater amount of parking real estate.
When everyone wants to live close together (ie in LA near where they work, socialize, etc. not in middle of Nebraska) that puts a real pressure on space, and drives up the cost for real estate.
Even if you want to increase density by building higher buildings, the cost of those condo/apartment towers now must factor in a parking garage pedestal taking up 1/3 of its height, and so must offices, shopping centers, etc.
I don't think the ratio of parking spaces per car needs to be reduced. Rather it needs to be recognized, and thus reveal the cost of policies that lead to one car per person. If you can reduce the cars per person ratio, you reduce the number of parking spaces required at a 3x rate.
Cities are great because of all the different things you can get to. However cars spread the city out, and in this in turn means you can't do as many things. You can still do a lot, but eventually the distance (distances in cities are measured in time not meters!) is unreasonable and so you can't get someplace in your city. Dense cities enable more things. If you just want to go to walmart - so do everyone else so no problem. However if you have a niche interest you may discover not enough people live within range to support a place for your interest even though across the entire city there are enough people.
How are the cars limiting here? It's quite the opposite - you can have a special interest shop/venue in a cheap mall in some industrial area and get enough customers who can reach you by car. Without the car ubiquity you'd need to get into expensive real estate in the city center to get potential customers and charge them for your rent, which is fine if you are dealing in, say, collectible wines or artisanal Swiss timepieces and no business if you want to sell Gundam models or knitting sullies.
I think the implicit attitude that your comment seems to have of one car per person is the real issue.
Okay yes, but we're not talking about a hypothetical city in a hypothetical world in which there are 3 million people who share 10 cars. We're talking about Los Angeles, which everyone reading this thread knows (or can Google) has, in the real world, close to one registered car per person. We're talking about this in a thread about parking minimums in the US, which are almost always found in cities that have approximately one car per person, or at least one car per household.
In that sense, no number ever shows anything "by itself" because meaning is always constructed contextually, but at some point we have to all understand context because it's both tedious and Sisyphean to spell everything out every time.
And the more often the car is running, the fewer parking spots you need, so shared cars help here too.
But neither would beat a well organized hierarchical and capillary mas-transit.
An interesting metric but not definitive and comparable.
Although it should be unnecessary to point it out, I would nevertheless say this "3 park space for car" is equal to "there are 3 spot for you to stand".
Now reducing parking spaces per car might put pressure to reduce cars per person, or implement alternatives to allow fewer cars per person, which would actually improve land usage.
It seems somewhat obvious that you may need more parking spaces than cars since they move to different places throughout the day.
The question people are asking is how can cities make it easier both for people to live in them as well as move around them without needing a car to do so. By removing parking minimums, it implies that people will have a harder time driving, which will entice them to use other means to get around. But, the big issue is that cities also need to invest in those other means of getting around. That means making micro-mobility easier with protected infrastructure, more bus service, more light-rail, etc. LA had a light rail service until GM, Standard Oil, and Firestone Tire organized a shell company to buy out the system and eventually tear it out. They did the same thing to the Key System in the East Bay of the Bay Area. https://en.m.wikipedia.org/wiki/National_City_Lines
Don't fool yourselves. There are many ways to reduce housing costs and increase housing supply.
Reducing parking spots is lame.
The issue isn't parking spots, the issue is that construction has had 0 efficiency gains in the last 50 year. Its cheaper to produce a car, grow food, produce computer chips, etc. Its not cheaper to build a building or a parking structure. Make it cheaper to build and it will solve house prices. And its not raw materials that make it expensive. There is no automation. We still pour concrete and frame buildings that same way we did 50 years ago.
I'm sure we could thrown up a hunk of concrete and rebar in the middle of nowhere in area with no environmental regs real cheap, especially if only care if it stands until the check clears.
I have, I've lived in such a place. I walked to work, about half an hour each way. It was quite pleasant.
To fix this we should bulldoze things and build more room for my car!
I have to be able to park my car! What else could I possibly do instead?!