Sadly, Mumford’s prophecy has come to pass. But I believe, if we can seize the opportunity, that autonomous cars hold the seeds of an urban renaissance, giving us a fighting chance to reverse the most disastrous consequences of the first 100 years of the automobile. It will take imagination, foresight, and political will. And the stakes are high, so we should start now.

Lest I be accused of irrational optimism, I’m well aware of the danger that autonomous cars will make things worse rather than better. As driving becomes radically more convenient, people may simply drive more and move farther away from cities. Perhaps traffic will improve temporarily, but just as with highway-widening, the increase in total driving will inevitably lead it to return, worse than before.

Avoiding this nightmare and making autonomous vehicles a force for good will require four ingredients:

Shared Vehicles

Fagnant et. al. attempted to figure out what size fleet of shared vechicles would be needed in a mid-sized city like Austin to achieve the same level of mobility as currently exists. They found it would take roughly one tenth the number of vehicles currently on the road, if those vehicles were shared. Because they’re in use more-or-less constantly, there’s no need to park them for long periods of time. If we don’t need to park our cars, we can reclaim a truly vast quantity of urban land for more productive uses, and start to knit them back together as walkable places.

Clear Price Signals

In many urban areas, it is already cheaper to go carless than to own a car, and it’s an increasingly popular choice. But the price signals are really hard to see - a car is a major purchase, and once you have it, you mentally discount the cost of the vehicle itself, maintenance, depreciation, etc. in each incremental trip. The cost of the infrastructure - parking, roads, etc. - is also completely hidden - as are the cost of lost time spent in traffic or circling for parking, and the health costs of emissions in respiratory and other illnesses and premature death. If we’re going to avoid a world where autonomous driving means more driving, we need to internalize all of these externalities. More on how in a future post.

Full Autonomy

In December 2015, the California DMV released a draft proposal for regulation of autonomous cars that includes the requirement that there be a steering wheel and a licensed driver behind it, ready to take control at any moment. While understandable,this would be a terrible mistake. For the elderly and disabled, it would destroy all of the substantial benefits that autonomous mobility promises. It would make real shared autonomous fleets impossible. And most importantly, it would undermine the potentially enormous safety benefits. It’s already obvious that humans are terrible drivers. They have no place at the wheel of a deadly moving projectile. Fortunately, the Federal government seems to understand this.

Enlightened Planning

In a world of on-demand shared mobility, opposition to new development should become less vociferous, as the argument that density causes parking shortages and congestion will evaporate. As cities get denser, they will become more walkable and bikeable. Partly because there will simply be more of the stuff that people crave closer together. But also because, as humans stop driving themselves, biking and walking will become orders of magnitude safer and thus even more appealing.

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For a century, the forces unleashed by the automobile have been inexorably pulling our cities apart. By putting these four ingredients together, we can start to undo the damage. On the other hand, gas prices are at historic lows. There are entrenched political and economic forces that will fight these developments tooth-and-nail. And people love cars. They are both intensely personal possessions, and the objects of a century-long romantic dream of freedom. Which vision will prevail?