Photo by imnewtryme on Flickr.

Yesterday, I argued that we will start seeing autonomous vehicles operating on our roadways in 7-12 years. But whether self-driving cars hit the roads 5 years or 30 years from now, they will bring major changes in our transportation system and even our society.

They’ll be more often in use, less often parked: Since most cars are parked for 98% of their existence, a self-driving car can be put into use when it would otherwise be idle. This can kill several birds with one stone. After dropping off its passengers, the car can do double duty as a taxi, delivery vehicle, or just get out of a congested area.

A model like Zipcar becomes an on-demand taxi service with self-driving cars. And a model like SuperShuttle becomes a micro-jitney service with self-driving cars. Now, SuperShuttle only serves airports, and the driver and dispatcher try to create the most efficient routes based on their ever-changing flow of customers. A computerized system could make this work everywhere.

If it’s not needed, a self-driving car can park itself at an offsite location, thus eliminating the need to build large amounts of parking at desirable (and expensive) locations.

They’ll reduce labor costs: A self-driving car needs no operator, thus removing human labor from the equation. Self-driving cars will put taxicab drivers out of business. What will those thousands of people do with their skillset when a computerized system makes them obsolete?

They’ll expand access to transportation: The process of driver training and licensing will be obsolete, and the requirement that people be 16 or 18 to drive a car will be irrelevant since now there are no drivers, only passengers.

This is great news for the disabled, especially the sight-impaired, as well as for adults who have lost the ability to drive. Will we create some new paradigm of age restrictions for being an unattended passenger?

Self-driving cars eradicate the car-ownership paradigm. If you can easily and affordably (remember, no labor to pay) book taxi service from your smartphone, more people than ever will eschew the costs and annoyance of car ownership.

They’ll be safer: Self-driving cars likely won’t make human errors. Auto crashes typically claim around 38,000 lives per year, and that’s been true for decades. Over 80% of these are attributable to human error, either negligence, distraction, incapacitation, malice or other uniquely human quality.

They’ll reduce congestion: Self-driving cars can manage congestion as a system, rather than a collection of self-interested units. A lot of congestion stems from the way each driver acts in his own self-interest. For example, changing lanes might (or might not) help one individual driver, but hurts the overall performance of the road. Speeding into a gap and then braking also creates worse congestion overall.

If all cars are self-driving, then they can cooperate to mitigate congestion. For instance, the cars could all slow down to 35 mph past a crash or police traffic stop, rather than allowing the speeding up and slowing down and rubbernecking which lead to traffic and more crashes. Over time game theory and other disciplines will help engineers devise ever more complex strategies to keep the system performing optimally.

They’ll make current transit economics obsolete: Self-driving cars represent a major existential threat for current and planned transit systems. Our current transit paradigm relies on capital and operational subsidies. We can’t charge riders enough to pay for everything that goes into making transit work. As we raise fares, more riders forego transit and choose the automobile.

If, as I suspect, self-driving cars are handled primarily in the private sector, their operations will not be subsidized, and their relative convenience and utility will call into question the logic of investing billions into the construction and operation of transit systems.

They won’t last as long: Automobile manufacturers will have to adapt the volume of vehicles they produce annually. While many fewer cars will be needed across the economy, those that are autonomous will be driving much more frequently. Their replacement cycle would be more similar to police vehicles, which only last around 3-5 years before wear and tear makes replacement a better option than repair.

Most passenger cars today spend around 98% of their time parked somewhere in between single-occupancy trips. Consequently, their average lifespan is between 15 and 26 years.

They can be electric: An electric self-driving car can go to where the charging stations are. DC and other governments are currently embarking on a campaign of spreading electric vehicle charging stations around the urban environment under the assumption that we must cast a wide net of these kiosks around so that they are convenient to an EV owner’s origin or destination. But in a few years, it is likely that this will be entirely unnecessary, and rather the car can take itself to a central charging location, like a power substation or electrified parking garage that can efficiently charge hundreds of vehicles on an as-needed basis.

They’ll change culture: A self-driving car eradicates a unique part of the American identity, the freewheeling mastery of the open road. We’ll wax nostalgic for what we’ve lost, but everyone will benefit from the gains.

A world with self-driving cars would operate very differently than the one we currently live in. I would say that’s mostly for the better. As urbanists, we’ve often succumbed to a gut reaction that cars are bad, transit is good. However, the reality is that it is not cars that are bad, but the single-occupancy driver paradigm that is so damaging to our environment, urban fabric and quality of life.

We still live in an America where 78% of people drive to their jobs by themselves. I’m convinced that we’re about to see that start to change as self-driving cars become a reality. It is time to start having the conversation about how we want this future to unfold in order to best plan for a very different world.