ROAD TRIPS. DRIVE-THROUGHS. Shopping malls. Freeways. Car chases. Road rage. Cars changed the world in all sorts of unforeseen ways. They granted enormous personal freedom, but in return they imposed heavy costs. People working on autonomous vehicles generally see their main benefits as mitigating those costs, notably road accidents, pollution and congestion. GM’s boss, Mary Barra, likes to talk of “zero crashes, zero emissions and zero congestion.” AVs, their champions argue, can offer all the advantages of cars without the drawbacks.

In particular, AVs could greatly reduce deaths and injuries from road accidents. Globally, around 1.25m people die in such accidents each year, according to the WHO; it is the leading cause of death among those aged 15-29. Another 20m-50m people are injured. Most accidents occur in developing countries, where the arrival of autonomous vehicles is still some way off. But if the switch to AVs can be advanced even by a single year, “that’s 1.25m people who don’t die,” says Chris Urmson of Aurora, an AV startup. In recent decades cars have become much safer thanks to features such as seat belts and airbags, but in America road deaths have risen since 2014, apparently because of distraction by smartphones. AVs would let riders text (or drink) to their heart’s content without endangering anyone.

Evidence that AVs are safer is already building up. Waymo’s vehicles have driven 4m miles on public roads; the only accidents they have been involved in while driving autonomously were caused by humans in other vehicles. AVs have superhuman perception and can slam on the brakes in less than a millisecond, compared with a second or so for human drivers. But “better than human” is a low bar. People seem prepared to tolerate deaths caused by human drivers, but AVs will have to be more or less infallible. A realistic goal is a thousandfold improvement over human drivers, says Amnon Shashua of Mobileye, a maker of AV technology. That would reduce the number of road deaths in America each year from 40,000 to 40, a level last seen in 1900. If this can be achieved, future generations may look back on the era of vehicles driven by humans as an aberration. Even with modern safety features, some 650,000 Americans have died on the roads since 2000, more than were slain in all the wars of the 20th century (about 630,000).

To take advantage of much lower operating costs per mile, most AVs are almost certain to be electric, which will reduce harmful emissions of two kinds: particulates, which cause lung and heart diseases, and climate-changing greenhouse gases. Even electric vehicles, however, still cause some particulate emissions from tyre and road wear, and the drop in greenhouse-gas emissions depends on how green the power grid is. The switch to electric vehicles will require more generating capacity (UBS estimates that it will increase European electricity consumption by 20-30% by 2050) and new infrastructure, such as charging stations and grid upgrades. For urban dwellers, the benefits will be better air quality and less noise.

Whether AVs will be able to reduce congestion is much less clear. The lesson of the 20th century is that building more roads to ease congestion encourages more car journeys. If robotaxis are cheap and fast, people will want to use them more. Yet there are reasons to think that the roads would become less crowded. Widespread sharing of vehicles would make much more efficient use of road space; computer-controlled cars can be smart about route planning; and once they are widespread, AVs can travel closer together than existing cars, increasing road capacity.

What is certain is that riders who no longer have to drive will gain an enormous amount of time that can be used to work, play or socialise. “Americans can take back a total of 30bn hours per year that they now spend driving, sitting in traffic or looking for a parking space,” says BCG.

Yet to think about AVs as a fix for the problems caused by cars is to risk falling into a familiar historical trap. This is exactly how people thought about cars when they first appeared: as a fix for the problems caused by horses. In the 1890s, big cities around the world were grappling with growing volumes of horse manure and urine and the rotting bodies of thousands of dead horses, spreading disease. In 1894 the Times of London famously predicted that by the 1940s every street in the city would be buried under nine feet of manure. By comparison, cars seemed clean and hygienic, a key reason why they were adopted so quickly in the 20th century. “Cars replaced something that was in many ways far worse,” says Donald Shoup of the University of California at Los Angeles. “But because of bad planning, they had unintended consequences.” What might follow from AVs?

Shops that come to you

Cars transformed retailing, giving rise to suburban malls with lots of shops and plenty of parking. AVs, combined with the rise of e-commerce, could transform it again. “The Walmart of the future might be fleets of vehicles ready to drop off anything that you might get at a Walmart,” says Peter Norton of the University of Virginia. Or you might order an AV to take you home from work, and arrange to have your groceries, or a meal, waiting for you when you climb aboard. And why should shops, restaurants or other facilities be fixed in place? Coffee shops or food stands could restock at a central depot and then migrate to business neighbourhoods in the morning and entertainment districts in the evening, suggests Chenoe Hart, an architectural designer at the University of California at Berkeley. Mobile shops selling items such as shoes, clothes or cosmetics could visit particular neighbourhoods on a regular schedule, or when hailed by a customer. “It gives us flexibility to reassign space,” says Ms Hart.

Carmakers are experimenting with delivery vehicles that draw up outside a customer’s home, announce their arrival by text message and allow items to be retrieved from a locked compartment by entering a code. Low-cost deliveries using AVs could stimulate local production of all kinds of things, most notably food. Already, food-delivery services like UberEats, Deliveroo, Seamless and GrubHub have given rise to “ghost restaurants” that produce food for delivery only, centralising food production in a few kitchens. Cheap autonomous deliveries could make this kind of model more widespread.

Another possibility, says Johann Jungwirth of Volkswagen, is that restaurants or retailers might cover the cost of travel to encourage customers to visit them. Fancy restaurants might lay on luxury AVs to ferry sozzled customers home, as part of the cost of a meal. Retailers could offer to pay for shoppers’ rides. Ride-hailing networks have a lot of customer data that could be used to target in-vehicle advertising. Hail an AV to go to one shop or restaurant, and you might see ads for a rival. Riders may be offered cheaper rides with ads or more expensive ones without them.

Self-driving vehicles could also deliver other services, letting you work out with your personal trainer on the way to the office or summon a hairdresser to your home. Toyota’s e-Palette vehicles are boxes on wheels in different sizes that can be kitted out as mobile shops, offices or beauty salons. Moreover, AVs could give rise to new kinds of social activities, just as cars provided teenagers with new social opportunities. Ride-hailing networks might group together people with similar interests or friends in common when assigning rides. Or they might work with a dating app, pairing people up with a potential match when they take a ride. AVs might also function as mobile party venues, or double as sleeping pods on long trips, offering an alternative to hotels and low-cost airlines.

A watchful eye

What unintended consequences might there be? One much-heralded benefit of AVs is that they will offer freedom and independence to people who cannot drive cars: the very old, the very young and the disabled. Such vehicles are already ferrying around people in retirement communities, and one of Google’s videos shows a blind man doing errands in an autonomous car. But AVs could also encroach on freedom by invading people’s privacy. Robotaxi operators will chronicle their riders’ every move, so they will end up knowing a great deal about them. Some taxis already record riders for security reasons; robotaxis will surely surveil both their passengers and their surroundings to protect themselves. Police investigating a crime will ask AVs in the vicinity what they saw.

If people no longer drive cars, one consequence may be new forms of segregation, notes Ms Hart. Access to some places may be restricted to certain riders or robotaxi networks, just as some online services are “walled gardens” or cannot be accessed on all devices. She thinks there may be a need for a physical equivalent of “network neutrality” rules, to ensure that all locations are equally accessible to all AVs. In authoritarian societies, AVs could be a powerful tool of social control.

AVs could also trigger a shortage of organ donors (many of whom are young people killed in car accidents) and a drop in smoking (more than half of all tobacco sales in America are made at petrol stations, which will vanish, notes Mr Evans). And if cars are no longer symbols of independence and self-definition for the young, other things will have to take their place. Like cars before them, AVs will change the texture of everyday life.