DRIVING THROUGH SILICON VALLEY on freeway 101 in busy Friday lunchtime traffic, Google’s Chris Urmson flicks a switch on the steering wheel. A green light comes on to tell him and your correspondent in the passenger seat that the Lexus SUV is now driving itself. A Jeep cuts across it, brakes and exits to the right, followed by a Toyota pickup truck that gets rather close. Each time the Lexus backs off smoothly, maintaining a sensible distance, then accelerates again once the road ahead is clear.

Google first revealed in 2010 that it had been working on self-driving cars. This fits in with its work on mapping and software and might give users extra time to surf the web, boosting Google’s profits. Last year the company released a video of a blind man sitting in the driver’s seat of one of these (albeit with a passenger as backup), being taken to buy takeaway tacos and collect his dry cleaning. Sergey Brin, one of the internet company’s founders, expects its autonomous driving system to be ready for the market in five years. That may be optimistic, but by the 2020s some cars that drive themselves most or all of the time could well be in volume production. This will have big consequences.

The idea of self-driving cars as a means of reducing accidents and congestion has been around for a long time. One of the most popular exhibits at the 1939 New York World’s Fair was “Futurama”, a depiction of a city with cars remotely controlled by radio. In the 1980s and 1990s the European Commission sponsored a programme of research on automated driving, Prometheus. In the mid-2000s the Pentagon’s research agency, DARPA, launched its Grand Challenges, offering prizes to driverless cars that did best at navigating a tricky course. In the first of these, in 2004, none of the robot cars completed the course. In the third, held in 2007, six cars made it. The winning team’s technical director was Mr Urmson. Its main advantage over its rivals was that it had mapped the course in fine detail, something that his current employers are busy doing for the rest of the planet.

But even before such prototypes have proved themselves, the technology is already arriving in instalments as carmakers introduce sophisticated “assisted driving” features as options, even on mass-market models. European buyers of the Ford Focus, a mid-sized car, can now leave it to drive itself and maintain a safe distance in steady traffic. The car can measure a parking space and steer itself into it. It reads road signs and admonishes the driver if he breaks the speed limit. Such gadgetry also increasingly makes decisions on the driver’s behalf and overrules him in an emergency, for instance, braking to avoid a crash.

Other technologies are beginning to make this easier. First, the mechanical links between the controls and the working parts are progressively being replaced by electronic ones. Second, cars now have a rudimentary version of “black box” data recorders to collect information on the moments just before an accident. Insurers have already begun to offer discounts to motorists who agree to have more sophisticated ones that monitor their driving all the time.

Basil Enan, the boss of CoverHound, an online insurance broker, says that as well as giving discounts to drivers who install black boxes, insurers are offering lower premiums on cars with assisted-driving features because they reduce accidents. He thinks that in future “manual driving” will increasingly be penalised: “The more miles you’re logging on autopilot, the less you’re going to pay.” This will give motorists an incentive to use the assisted-driving features on their cars. Carmakers, for their part, will have an incentive to keep adding more to maintain high scores in the widely publicised safety tests that help them sell their models.

Safety-enhancing gadgets on cars tend to start out as optional extras, then get incorporated into “best practice” standards promoted by independent bodies like Euro NCAP, and eventually are made compulsory. Ubiquitous black boxes in road vehicles will provide a mass of data likely to demonstrate the effectiveness of automated-driving features, which will prompt calls to make them obligatory.

Let car speak unto car

With demand for advanced in-car navigation and entertainment systems growing, vehicles are becoming ever better connected. From next year cars sold by GM in the United States and Canada will come with fast 4G mobile broadband. Improved connections will also make it possible for cars to send hazard warnings to each other, to receive a constant stream of information on the traffic and weather ahead and even to interact with signals as they approach junctions.

In Ann Arbor, near Detroit, 2,800 cars, lorries and buses have been fitted with devices to send and receive such alerts. Some have just a simple beacon that informs other traffic of their location, speed and direction. Others have more elaborate kit that can detect, for example, if another wired-up car, out of sight around the next bend, has slammed on its brakes. Carmakers are keen to support such research. Ford has provided eight sedans for this experiment and is using them to try out various ways of alerting drivers: sounds, warning lights, even projections onto the windscreens using a head-up display. Jim Sayer, who is overseeing the trial, says drivers seem interested too: when his team went to local schools and a hospital looking for volunteers to have their cars wired up, they got far more than they needed.

In the Ann Arbor study it is human drivers who receive and act on the alerts, but in future cars will be able to respond automatically. Governments will want to ensure that all road traffic gets connected up to reduce accidents, congestion and vehicle theft. Having a transmitting beacon on every car would also be good for dynamic road pricing, with charges depending on the type of vehicle and the time of day. Brazil’s government is already preparing legislation that will require all cars to have a beacon broadcasting their make, model, registration number, age, fuel and engine power.

Decades of road-safety legislation will have to be overturned before cars can roam the streets without a qualified and sober driver at the controls

So it seems clear that driving will become increasingly automated in the next five to ten years. But will cars get to the point where they do not need a driver at all? Some carmakers are sceptical. Jürgen Leohold, VW’s research chief, says perhaps in 50 years, but he does not look further ahead than 20 years and does not expect a fully autonomous car by then. He thinks over that timescale there will always be situations where the computer will have to pass the controls to a human. Mr Leech of KPMG reckons that fully autonomous cars would still crash sometimes, so manufacturers might be reluctant to market them for fear of damaging their reputation. But Renault-Nissan’s boss, Carlos Ghosn, is more optimistic: “I don’t see any impossible obstacle. I think this is something you are going to see on the horizon of 2020 because the technologies are getting mature.”

A number of technical obstacles remain. For driverless cars to work, every inch of road, every junction, road sign and signal everywhere will have to be mapped in perfect detail. But this is being done anyway to support navigation systems for both cars and smartphones.

Mr Urmson says that self-driving software will gain experience as it is tested, just like a human driver. The difference is that everything it learns will become available to every other car with the same software. Google’s driverless cars have already clocked up more than 700,000km, which Mr Urmson reckons is more than he will drive in his lifetime. Computers do not get tired or distracted and will be far more aware of their surroundings than any human. In a tricky situation, says Mr Urmson, the computer will do what a human would: brake hard and hope for the best, but do so more quickly and expertly.

The technology seems likely to be ready before all the questions of regulation and liability have been sorted out. Three American states, Nevada, California and Florida, have passed laws governing the testing of driverless cars on public roads, which had previously been a legal grey area. But that is just the start. Decades of road-safety legislation will have to be overturned before cars can roam the streets without a qualified and sober driver at the controls, and accidents involving driverless cars are bound to attract some lawsuits.

A study in 2009 of the legal risks of increasingly autonomous cars by the RAND Corporation, a research body, suggested two possible solutions: changing the liability laws to require courts to take the benefits of driverless technology into account when punishing carmakers for any failings; and limiting motorists’ ability to sue in state courts when driverless technology mandated by federal laws fails to prevent an accident. By way of a precedent, the study noted that some states already have laws forbidding drivers from going to court over minor accidents, requiring them to claim on their insurance policies instead. Mr Urmson notes another precedent: the 1929 Warsaw Convention limiting airlines’ liability to passengers in the event of loss and injury, which was introduced in an effort to give air travel a lift. But Dave Cole of the Centre for Automotive Research in Michigan fears that given America’s taste for litigation, the truly driverless car will probably emerge somewhere else first.

Alex Padilla, a member of California’s state Senate who promoted the law on testing driverless vehicles, is confident that most people will want it (though there will always be some who enjoy the sport of doing their own driving). It will bring huge benefits. People who spend hours driving every day will get a chunk of their life back, to work, rest or play while they are on the road. Less congestion means less wasted fuel and fewer emissions. Volvo has already demonstrated a way of packing autonomous cars together in “road trains”, greatly increasing the capacity of roads while reducing traffic jams. The aerodynamic effects of road trains offer scope for even greater environmental gains: a 1995 study by the University of Southern California showed that they can improve fuel efficiency by up to 30%.

Google’s stunt with the blind man points to another big advantage of the driverless car: it can provide mobility for the growing number of older and disabled people in the rich world and in some emerging markets too. Mr Ghosn points out that a baby born today might easily live to 100, but from the age of about 75 many people will suffer health problems affecting their ability to drive. Parents, too, will welcome a car that does the school run for them. And teenagers will no longer be put off getting their first car by tough driving tests and steep insurance rates because they will need neither licences nor personal insurance. Business travellers may sleep in driverless Winnebagos that hurtle down the motorways at night, delivering them to the next morning’s meeting.

Electronic guardian angels

Most important of all, the driverless car will drastically reduce the carnage of road accidents and the colossal medical costs associated with them. A new study by the World Health Organisation shows that such accidents kill a shocking 1.24m people a year worldwide. McKinsey’s Mr Kaas says that in China and other countries where most motorists are fairly new to driving, safety features are an important selling point for cars.

Cars on autopilot will also radically change the car-insurance business. Most of the cost of this is to cover liability for accidents, which will become rare, so revenues will come down a lot. Stricter speed limits, safer cars, seat belts and the like have already brought a steady decline in casualty rates since the 1960s, when Ralph Nader wrote his anti-car diatribe, “Unsafe at Any Speed”, but now there are signs that in America “distracted driving”—texting, phoning and tweeting at the wheel—is reversing the trend.

If automated driving means more people are able to use cars, and more cars can safely be fitted onto the same roads, that should be good for the motor industry. In time cars that have hardly any accidents should also become cheaper to make, because they will not need to be so robust. But in the shorter term the carmakers will have to add lots of expensive sensors, computing power and software to their models, which will make it harder to turn a profit. Larry Burns, a former GM executive who now works on driverless cars and other transport issues, says the technology looks inevitable, but it is hard to see how it will deliver value for car companies’ shareholders.

As car users do less driving and spend more time as passengers, they will also become less aware of how well a car performs, which is currently a big selling point. Stefano Aversa of AlixPartners worries that cars will become commoditised, rather like dishwashers. Makers may have to change their marketing to put more emphasis on styling, interior comfort and brand. Mr Ghosn thinks they will find a way: “What you market in a car is not about what you use but about what you dream.” John Eddy of Arup, a big firm of consulting engineers, says town planners, property developers and builders need to start thinking about the effect of self-driving technology on demand for roads, parking, housing and so on. So far there is little sign that this is happening. But the driverless car is definitely on its way.