Ever since I moved to San Diego last year without owning a car, people have felt sorry for me. They offer me rides. They wonder where I buy groceries. They ask me how I feel about being nature-deprived. They ask me how I can stand to ride the bus.

I usually smile and nod and acknowledge what they are saying and tell them it really isn't so bad. I rarely tell them that they are making a fundamental mistake: They are equating owning a car with using a car.

I belong to Zipcar, and there are two Zipcars parked at all times in the parking garage in my apartment building – a MiniCooper wagon and a Ford Escape SUV – that I can rent whenever I want. In fact, they are located closer to the elevator than my two eternally vacant parking spaces. I also belong to Car2Go. Right now, my smartphone tells me there are six two-seater SmartCars parked within 1,000 feet of my apartment, all available for me to rent on a per-minute basis.

Avis is located four blocks away. Sometimes I rent a car for the weekend, though that seems awfully old fashioned these days. When I have to drive for work – my office is five blocks from my apartment – I have access to the city motor pool, which is located right downstairs in a parking lot outside my office building. I usually take a taxi to the airport (two miles away); from my apartment window I can see whether there are any taxis waiting for a fare at the Doubletree Hotel across the street.

And when I don't know what else to do I call Uber X.  Right now my smartphone says there are five Uber X vehicles within four blocks of my apartment.

Cars? I have more cars than I know what to do with. I use cars all the time, in order to go all kinds of places, and I am never without access to a car.  My overall automobile cost is probably less than half of what it was when I owned a car – because I usually pay for a car only when I am traveling in it, not when it is just parked somewhere.

I'm well aware that I am on the leading edge of this whole "car-sharing" thing and that the vast majority of people don't have the same options because of where they live and work. But the fact that I am doing just fine without owning a car in a traditionally suburban place like San Diego suggests that something important is going on, at least in modern urban neighborhoods: Our complete reliance on a "monoculture" of owner-occupied automobiles is being augmented with a much more varied ecosystem that includes not just alternatives to driving, but many different ways to use a car.

The urban transportation infrastructure obviously also includes walking, bicycling, and rail and bus passenger service. (Because I limited my discussion above only to cars, I didn't even mention that I can walk to the Santa Fe Depot in downtown San Diego from either my apartment or my office, making it easy for me to get to downtown Los Angeles without a car.) In California cities, these choices have not traditionally been "robust," as they say. But when they are augmented by the range of car-sharing options I listed above, the entire system becomes a much more powerful option. You can take a regular bus or train to a destination and then use a car-sharing service like Uber X if you get stuck later on in the evening when service is bad or nonexistent. (I have done this several times.) Or – perhaps most important – you can use a car-sharing service as the "last-mile" solution to get to and from a rail stop. (This is part of the reason why car-sharing services have been more successful in Los Angeles than even the vendors thought they would be. In such a spread-out city, solving the last-mile problem is huge.)

At the recent Southern California Association of Governments annual general assembly, transportation infrastructure guru Dan Sturges noted that any successful transportation system has to function like the vines that Tarzan uses in the jungle. Swinging from one vine isn't enough. The next vine always has to be there, ready to grab, or else the whole system falls apart. All transportation systems work like this, but if they work well we don't even notice. For example, we routinely take off on long car trips, confident that the infrastructure of well-placed gas stations will be available to us before we run out of gas.

The same is true for car-sharing. The more options we have, the more powerful the system becomes. We can move about the city using lots of them, confident that the next swinging vine will always be there.

Obviously, many people – especially in suburban locations – will always have activity patterns that will require them to own their own cars, drive them everywhere, and leave them parked most of the time. But for even semi-urban locations – such as old close-in single-family neighborhoods adjacent to commercial corridors – the swinging vine option is pretty viable.

Indeed, the swinging vines can help transform these neighborhoods much faster than public transit alone ever could do. And success is likely to feed on itself. The more people use these options, the less parking these neighborhoods are going to need. Obviously, heavy use of Uber or Lyft cars, which are constantly circling around, reduces the need for parking. But research also suggests that one Car2Go or Zipcar – which the user has to park somewhere – has a similar impact becauseas a short-term rental car it will be driven more and parked less. Plus you can park two Car2Go SmartCars in one parking space.

When less parking is needed, more land can be devoted to new buildings, which means a greater concentration of both people and destinations in one place, which means even less need for parking and greater opportunities for using the swinging vine.

From this perspective, the traditional suburban model seems pretty archaic – and expensive. Cars that are parked virtually all the time, at great expense to their owners? Huge amounts of land devoted to parking that could be devoted to more profitable or more human-scale uses? How rigid! How inflexible! How expensive! How 20th-Century!

Obviously, this suburban model will be with us for a long time because so many people live and work in suburban locations – often with long commutes. They will have little choice but to own their own car, drive it everywhere they go, and park it virtually all the time. And huge numbers of people will continue to make the suburban choice. But for urban and semi-urban neighborhoods, car sharing seems like an almost miraculous way out of the conflict between density and driving. And in those neighborhoods, the ongoing and often inevitable transition away from the suburban model will become more viable, cheaper, and much easier to plan for.