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Comment by smt88 | Hacker News Reader

LA is a disaster for transit and housing, but your numbers aren't a problem on their face.

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.

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> LA is a disaster for transit and housing, but your numbers aren't a problem on their face. 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.

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.

No, those numbers don't show that by themselves. That's because there's nothing about cars per person, only spaces per car. Cars would not be a problem at all if there were even 50 spaces per car... but only a total of 10 cars!

I think the implicit attitude that your comment seems to have of one car per person is the real issue.

> No, those numbers don't show that by themselves. That's because there's nothing about cars per person, only spaces per car. Cars would not be a problem at all if there were even 50 spaces per car... but only a total of 10 cars!

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.

Why is 3 parking spaces per car inherently unsustainable?

If everyone needs to have a car to get around that's 3 parking spaces per person. Or 6-12 parking spaces per household.

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.

3 parking spaces is ~750sqft. A moving car is another 2000sqft. Once population density passes ~3 stories, the geometry stops working. Once drive time exceeds an hour or two, the math stops working. It's the urban rocket equation.

They’re not additive - a car can’t be parked and moving at the same time.

This is in response to a thread discussing the fact that LA has three parking spots per car, and they must (by counting) be mostly empty.

It isn't unsustainable. However it is limiting. That is a lot of space that is 2/3rds empty yet not really usable for anything else. Worse, cars are heavy and so it isn't practical to go vertical with parking spaces (we can/do build parking ramps - but they are a lot more expensive and so few want to pay to park there, and even then there seems to be a limit to how tall you can make them)

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.

> 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.

Cars work best in low density. Eventually the total area of the city is so great that even though in theory you can drive across it, the total time that takes means some trips are unreasonable to do. If that story that sells Gundam models (I have no idea what this is so I assume it is a great example of a rare niche) is on the other side of the city it may be more than an hour drive at off peak times to get there and so for practical purposes it isn't in reach.

If it takes more than an hour of car travel then how long will it take without a car? I imagine your argument is that without cars the city wouldn't be as big, but the math doesn't work out: the travel time is proportional to the square root of the area while the additional area is linear. If a city with cars is triple the size of the same one without it would have taken only 1.7 time more to travel through. Public transit is way slower than 1.7x.

https://www.homeadvisor.com/cost/outdoor-living/pave-a-parki...

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.

The price to pave a lot is by far the least unsustainable part of the situation. Asphalt is cheap. The opportunity cost of the land use is much higher in all but the most rural of places.

If you think about it, three parking spaces take up way less space than 1 housing unit in LA.

Most housing units will have more than one person, and most of those people have cars. In most cities space dedicated to cars (parking and roads) covers about 50% of all land use. Housing, factories, stores, parks, churches, and the like are the other half.

Note that the above is about land area. Housing units are often stacked vertically, while car parking rarely stacked.

Where land is actually precious, parking gets stacked.

Where it is not stacked, it’s obviously not that terribly valuable.

Stacking parking is done. However it is so expensive to build that before it is worth stacking parking you are already building less parking than there is demand. The cost to park in stacked parking regularly means the costs to park there are high enough to make most customers look for alternatives. There are places just outside of downtown where the demand for cheap surface lot parking is higher than total parking spaces - but the people who go there would not pay for stacked parking. Thus while stacked parking exists, it is more costly than the value most people consider it to provide.

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.

There are always some cars being driven at any given time, so you could technically get away with even fewer spaces than cars. But the fewer spaces you have the less likely the available ones are near your destination.

You really can't average a wide area though, parking is a highly localized and cyclical problem set. During the night, most people will be at home, and during the day, most people will be at work. Your city will increase in population during the day as commuters from the suburbs commute to work. Events will happen in your city which will cause huge outliers in the demand for spaces.

Also, townhome rows typically have little to no street parking available because the driveways are so dense. This makes it impossible for friends to come over and park anywhere.

That's one thing that self-driving cars would help.

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.

Parking spaces per car is akin to toilets per person.

An interesting metric but not definitive and comparable.

we do not usually spend all our idle time in toilets, though .

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