> The problem I see with shared cars is that people like to forget stuff in their cars.

And the amount of your stuff will seem miniscule once you have kids. Car seats for different ages, extra food, water, diapers, sets of clothing, iPad holders, random toys, sports equipment, school supplies, and the list goes on.

> So now I'd have to carry my gun and ammo (or my sport gear, or ...)

Of course there are all kinds of little assumptions in our daily lives that would suddenly change and have to be addressed. In this case though, do you really need 170 sq. feet to store whatever you are carrying with you? Opening parking lots to development will generate enough value to provide a couple 12x18x72 inch lockers for each space removed. That still clears up over 98% of the square footage currently being taken up by parking spaces, and it would obviate the need to use cars for personal storage.

It might even lower theft since a big component of theft from automobiles is that a thief can look into a bunch of cars and only break in when something valuable enough is identified. And since lockers could be located inside where the people are, it would probably opportunities for would be thieves to have alone time with valuables.

> people like to forget stuff in their cars

If cars begin to be produced primarily for the purpose of transporting a single different person over and over again all day (with a smaller number of multi-passenger vehicles being produced for the relatively rare case of multi-passenger rides), then I imagine that eventually they would evolve a design that makes it more obvious when you drop things you are carrying. Currently cars[1] have all kinds of nooks and crannies for your wallet to fall into, because it's not that big a problem in most cases when you do that. But it would be fairly trivial to add a little fiber glass hip that sits flush with the seat. You would have to relocate the seat adjustment controls, but a lot of vehicles have already centralized those controls on the main console, and ridesharing vehicles would actually see enough benefit to consider such a change.

[1] this includes taxis because taxis fleets are made up of essentially consumer vehicles. This makes sense, because you always have at least 2 people in a taxi, so you can't really comfortably make it that much smaller. But if there were fleets of rideshared self-driving cars everywhere, most cars would only need to carry a single person, and you can drastically reduce the size of a one-person car without sacrificing comfort.

Edit: added third paragraph and the accompanying footnote

> with a smaller number of multi-passenger vehicles being produced for the relatively rare case of multi-passenger rides

You clearly have no children. Most people do though. Multi-passenger rides are hardly rare. Going to work is not the only thing people use a car for.

I have a child, that's beside the point. I also live in an Austin, TX suburb, so am pretty driving dependent. My comment is not naive due to inexperience with the occasional necessity of having to move multiple people around.

Objectively, the majority of driving is single passenger during commute time. I said multi-passenger trips are "relatively rare", that is, less common. I don't even see what could possibly be offending you in my comment. Yes, many people have children, and most of them drive mostly alone in one of their two cars 15 miles both ways to and from work. I don't see this as controversial. I'm not being remotely hyperbolic.

You are focusing on commute to work - yes, that's big. But people drive at other times too, and that is not rare at all. (That's the part I object to, that you think it's rare. Rare to me means less than 1% of the other, but actually it's more like 50%.)

Do you take your kids to buy groceries? To ship a package? You don't have to take them, but kids like to go.

You are still misreading what I've written? I said "relatively rare". That does not mean "rare". It means less common than the scenario being compared with. If lone commuting is 51% of driving, and multi-passenger is 49% of driving, it would not be inaccurate to say that multi-passenger driving is relatively rare when compared to lone commuting. I am not saying that multi-passenger trips rarely happen.

To reiterate, I am saying that more miles are driven single passenger (excluding hired drivers) than multi-passenger, and that is the only claim that I am making on the subject.

I trust we have that cleared up now. It means that once it makes sense to have driverless car fleets chauffeuring people around in cities, it will likely make economic sense to make a lot of those vehicles single passenger, because they can be made much more cheaply and run more efficiently. This is not really possible with the current consumer car industry, because consumers want the capability to drive more than one person (whether they have kids or not), even if most of the driving they do is alone. Likewise taxis are always moving at minimum two people when it's making money.

And I don't see any reason there wouldn't still be plentiful multi-passenger cars. I'm not trying to banish multi-passenger car trips from society. I'm not against them! They are just currently "relatively rare" in practice. I could see electric cars potentially increasing adult carpooling, or reducing it. For instance, maybe a car service has a fleet of minvans, and offers discount rates, but fills itself to capacity on the way to your general destination. Or maybe carpooling among adults with different starting and ending points ultimately essentially goes away, like if tiny single passenger driverless vehicles in constant use end up being more efficient than carpooling once all the numbers are in. Even in that case there would still be multi-passenger cars, because there are always going to be people who want to go on dates, or out with friends, adults that need to accompany kids and any number of other reasons that people choose to travel together. Driverless cars don't get rid of the need for multi-passenger cars. They get rid of the incentives that cause people to waste full size cars on one person trips. They unlock the potential for cars to further specialize to improve efficiency.

A consumer car needs to be multi-passenger. A driverless fleet car doesn't. It makes sense then that the fleets that service a given area would tend to try to balance the number of single passenger and multi-passenger vehicles in their fleet to match the demand for these two types of trips. That's really all I'm getting at with this line of thought. I'm not making a strong statement about the single vs multi-passenger composition of trips.

You did clear it up, except relatively rare does not mean that.

You can't make up new definitions for things and expect people to understand you.

Relatively rare has the same meaning as rare, except that it's rare only in comparison with the compared event, but might not be rare on an absolute scale.

So, no, 49% is not relatively rare.

1% is relatively rare, yet 1% of car trips is still an enormous number so is not actually rare. That is the only change in the meaning when you add the word relatively.

Getting back to your actual point, which was derailed by an incorrect word.

Multi car trips are less common, but not enough to make single passenger vehicles economically worth it. The majority of the expense on a vehicle is not the cabin. Once you paid to make a car, adding a bit more space for additional people costs only a little bit more, but greatly increases the flexibility.

So I don't expect the basic size of a car to change much.

Any child old enough for a school bus is also old enough for a self-driving taxi (age 8 or less). So that's most school/sports/activity runs out of the picture. And if you live in a city, your kindergarten and primary schools is generally 10 minutes' walk away or less.

But yes, there will be self-driving taxis of all sizes, just like there are ubers and rental cars of all sizes now.

> Any child old enough for a school bus is also old enough for a self-driving taxi (age 8 or less). So that's most school/sports/activity runs out of the picture. And if you live in a city, your kindergarten and primary schools is generally 10 minutes' walk away or less.

Thank God I won't ever become a teacher. I can already imagine kids saying "I forgot my homework in my taxi and couldn't call it back in time"...

How is that any different from "I forgot my homework on the bus, and it left immediately after it dropped me off."

Kids like going on trips (for example to the store, or the post office) with the parents, even when there is no reason for them to go. Multi-passenger trips will equally as common as single.

> No way at all to do so with an autonomous car.

How can you say that when they aren't even a thing yet? They could easily have a hotline to call in case of a situation like this, where they can manually pull it out of the queue and send it back to your location. It wouldn't be complicated or costly.

What if another passenger has already taken the vehicle? Then you'd totally depend on the honesty of a stranger.

Thanks but no thanks.

Meta: What's with the bizarre downvoting of non-anti-car comments in this thread? It's like anything that isn't 100% in favor of a shared-everything-screw-the-rurals-and-introverts economy is anathema or something. Maybe instead of downvoting, why don't you (whoever "you" may be) try to figure out why people have a different opinion than you? Maybe you'll find that the world is a heck of a lot bigger than you imagined and people exist who really do have different experiences and needs.

I cannot speak for the people down voting, but I can understand frustration with raising objections based on wants and desires which are not incompatible with cities focusing more on mass transit and self-driving fleets.

Folk who do live in rural areas won't be impacted much by cities transitioning to fewer cars. If their work requires commute into the city, I'm not sure why or how the commute would be any worse once self-driving cars are introduced. The idea is to reduce car dependence and the control cars have within cities. Assume for a moment that self-driving cars can participate nigh-perfectly in traffic with human drivers, and that they become the majority within cities. Would this not mean that as car ownership in cities goes down, available parking may decrease, but the demand for parking will also decrease?

As an introvert myself, I don't really have an issue with mass transit, since most everyone just wants to mind their own business. Once there are self-driving cars or once city culture shifts from car ownership to fleets of available cars, nothing is stopping you from having complete privacy as you travel if you desire it.

What I'm saying is that these concerns aren't incompatible with the share ideas. Your normal routine might be slightly different, but your wants and needs are not incompatible with the ideas at all.

I dislike downvote/upvote systems for discussion for the very reason you're expressing; it creates echo chambers, but it also expresses their position. I disagree with you, but I will tell you that it's because I think your wants and needs can be met perfectly if cities shift to less cars. Others apparently would rather just down vote to express their disagreement.

> Folk who do live in rural areas won't be impacted much by cities transitioning to fewer cars.

Oh they will because non-automated cars will have their insurance rates rising (once again, a tax on the poor, because rich people tend to concentrate in urban areas while poorer people will be outpriced to rural), they will be banned from driving in urban areas, and there will be no parking in the cities for them.

Because HN is full of urban hipsters whose viewport is limited to their city.

Do you refuse to go to restaurants because you're afraid that you might drop your wallet in a booth? Sure you can call the restaurant, but what if another customer already sat there and took it?

I'm pretty sure this problem isn't nearly as big as you think it is.

Restaurants don't drive off to somewhere else the instant you step out of them.

This was directed at the OP who said taxi's are OK because you can call the taxi company, but self driving cars aren't because if you don't call before someone else rides in the car you're stuff will be gone.

My response is that a restaurant works the same way. If you don't return or call before someone else sits there, you're stuff will be gone.

Addressing your point, taxis and buses immediately drive off after you step out of them. Do you avoid them because of this?

Ride-hailing apps will eventually take on urban storage as well. Want to avoid carrying something around? Press a button in an app. Want to use the thing you left? Press a button in an app. Want your stuff to head home with you? Press a button in an app.

Great, if you value those things so much you can pay to own your own vehicle (which you're basically using as a storage bin).

But I think that there are a lot of people who would gladly cut down on the $8K-$10K/year of car costs.

Indeed. I definitely use my car to carry a variety of tools and equipment with me all of the time, including emergency supplies. I'd have to start wearing like... a purse or something to keep even a fraction of that with me.

Regarding hours... realizing the bus to your hotel in Iceland is no longer in service at 2 AM in a snowstorm in March is super excitng.