How will driverless cars affect our cities?
Driverless cars are an [inevitable] reality
Google is the most conspicuous developer of autonomous vehicles, but it is hardly alone in pursuing this venture. Most automakers are competing to introduce their own driverless cars to the public, and are doing so piecemeal, system by system. The components of the upcoming driverless car are being introduced into current models as ever more elaborate mechanisms to aid the driver, such as self-parking features and automated collision avoidance systems. Recently, a group of researchers at Oxford University developed a self-driving system which can be installed in existing manually driven vehicles, and whose cost is hoped to fall as low as 150 dollars within a matter of years.
Driverless cars will dramatically affect urban form, in two ways
Many anticipated consequences of driverless cars have already received attention on this blog and elsewhere, such as their impact on the mobility of the elderly, on taxis and car sharing services and on the future of the car industry. A crucial aspect which has escaped attention is the impact of driverless cars on urban form, which I anticipate will follow two broad predictions:
Cities will greatly expand, again: Faster and more efficient transportation will convert locations that are currently too remote for most users into feasible alternatives, abundant with space. Like suburban rail in the early twentieth century and the mass consumer automobile that followed, driverless cars will generate a gradual, but dramatic expansion of cities.
Buildings and parking will be uncoupled, freeing up valuable land: After dropping off passengers, driverless cars will independently seek parking (or their next car-share customers) and they will show up for the return ride at the tap of an app. As soon as driverless cars are common enough, the demand for adjacent parking will dwindle and parking lots in areas where land is sufficiently valuable will be ripe for conversion to other land use. As parking in high-value areas is thinned out or altogether purged, the micro-structure of cities will change – you guessed it – dramatically!
Why will cities expand?
Driverless cars will make it less “costly” for people to travel a given geographic distance, partly because they will be free to engage in other activities while travelling, but primarily because of reductions in travel time. Unlike human drivers, autonomous vehicles will follow optimal routes given real-time traffic conditions without fail. More crucially, as soon as suitable roads such as freeways (or lanes thereof) are declared off limits to manual driving, driverless cars will travel – safely – at much higher speeds than we do today. Gains in efficiency will follow from coordinated traffic management protocols, too. Once vehicles communicate with each other traffic through intersections and merges will flow much more smoothly than permitted by today’s traffic signals, stop signs and merging lanes, leading to substantial gains in travel time (a partial, human-mediated step in this direction is explored in this article).
If people currently forego affordable, spacious dream homes because the associated commute is too long, a technology that condenses the time needed for commuting along the same route – and allows doing so in the back seat – will make those homes more agreeable. Similarly, businesses whose location depends chiefly on access to appropriate labor or clientele will find that potential locations which are currently too remote will become feasible. It will still be crucial for them to sit “close” enough to their talent pools or their customer base, but because what matters for “closeness” is travel time rather than geographic distance, these firms will be able to reap the benefits of more remote locations without giving up “closeness.”
How far will cities expand?
The extent to which cities expand will be determined by the extent to which travel times are reduced. The more efficient traffic flow becomes the broader the geographic range in which living and working becomes feasible.
Will we ever hit a point at which people are no longer interested in the extra space offered by more distant locations? This is unlikely. Today swimming pools and three car garages are common in suburban homes, but who would have imagined that possible before the advent of the mass consumer automobile? Perhaps the current equivalent is the wish voiced by some home buyers – typically just beyond the urban fringe – that neighbors’ homes be out of sight. That seems like a lot to ask in today’s suburbs, but it could well become the norm looking forward.
When will this happen?
Most estimates suggest that the arrival of the fully self-driving car on the consumer market will occur within a decade. Provided that it will be possible to install these systems in existing manually driven cars – much as hands-free cellphone devices can be installed today – then there will be no need to wait for the entire stock of cars to gradually be replaced, and a much faster process of adoption will ensue. The speed of the process will be determined by people’s willingness to give up the driver’s seat, and by the adaption of the legal environment, first to permit driverless cars and then to secure them an exclusive right of way (a separate lane on the freeway). Google and the automakers will go to great lengths to ensure that legal barriers are removed and that the driverless car is adopted quickly. The devotion of a separate right of way may be a more challenging feat, but it will be difficult to reject in light of the gains it will offer.
Following these developments, the gradual process of city expansion will take place over many decades, much as the ramifications of the mass consumer automobile continue to play out almost a century after its arrival.
Is this good news or bad?
Ultimately, the accelerated drift of the city past the current metropolitan fringe implies sprawl on an unprecedented scale. This is unwelcome news for those readers who, like this author, share a romantic view of dense urban life. But there is good news as well.
In his 1991 classic, “Edge City”, Joel Garreau wrote that it is “the suburban home with grass all around that made America the best-housed civilization the world has ever known.” If the widely spaced mansions of the future are to today’s suburban home what today’s suburban home is to yesterday’s urban tenement, then we are in for a glorious improvement in our material welfare. But this grates the city lover’s ear and there is good news for city lovers, too.
The uncoupling of buildings and parking
Once most people stop driving manually, there will be a far less compelling need for buildings and parking to be adjacent. This does not mean that all parking lots will be converted to other land use – the total need for parking will only be reduced if other developments like increased car-sharing take off. But it does mean that parking lots on the most valuable land will be available for infill development. Driverless cars will gladly navigate to abundant off-site parking that will substitute for the lost parking on less valuable land.
The places in which infill development takes place will become denser and more walkable. The busiest suburban shopping districts will probably be among the first to see their parking built upon, as will clusters of suburban office towers which often spread out over vast areas. In so doing these areas will attain a more urban feel.
Of course the broader environment will remain suburban, but the local clusters of walkable density we have today – primarily old town centers engulfed by sprawling metro areas – will be joined by a new breed born of formerly pedestrian-free suburban centers and infill development upon parking. Given that the overwhelming majority of dense walkable areas in this country were built before World War II, a new generation and breed of walkable locations is rather exciting.
And what about the carbon footprint, you ask?
Traveling greater distances at greater speeds will require more energy. Full stop. Car sharing will not undo this in spite of reducing the total number of cars, because car sharing essentially only does away with the time cars spend parked.
Under the pessimistic premise that each car continues to emit greenhouse gases at current rates, the effect of driverless cars on urban form spells out a magnified carbon footprint. But technology is not stagnant. Today’s gasoline powered cars are already far more efficient than they were even a decade ago, and the ongoing transition to electric vehicles means that the energy needed for traveling greater distances at greater speeds will no longer need to come from fossil fuels. Instead, cars can be powered by any source of energy used to produce electricity, including more sustainable alternatives.
Contrary to the intuition that associates rapidly advancing sprawl with environmental disaster, persistent progress in sustainable energy could ultimately dissociate the suburban lifestyle from the greenhouse gas emissions it implies today, severing an important link between sprawl and climate change. The crucial question in this respect is whether the greening of our energy will precede the brunt of our cities’ future spatial expansion or not.
An extension of this article was published in June 2013 entitled “Self-driving cars: A Force for Urban Densification or Expansion?”
Notes
The opening statement of this article originally said “Driverless cars are an imminent reality.” The weight of that statement is not in the speedy arrival of autonomous vehicles, which has since proven false, but in the certainty of their arrival, i.e. its inevitability. In this cross-posting of the article the opening statement has been modified to that effect.