Google takes its driverless car in a new direction. Source: Google

Google Taps the Brakes on Self-Driving Cars

Megan McArdle is a Bloomberg View columnist. She wrote for the Daily Beast, Newsweek, the Atlantic and the Economist and founded the blog Asymmetrical Information. She is the author of "“The Up Side of Down: Why Failing Well Is the Key to Success.”
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Somewhat quixotically, I am both a booster and a bear on self-driving cars. The technology seems obviously fantastic, necessary, laudable and so forth. It also seems to face a whole lot of market and regulatory obstacles.

To summarize my earlier writings on this topic: Even if truly driverless cars reduce accidents, they will probably increase overall liability, because a legal claim against a car company is worth a lot more than a legal claim against your typical middle-class person with a handful of assets that are protected in bankruptcy and a few thousand in the checking account. You can fix the liability problem by requiring drivers to stay attentive at the wheel at all times (which shifts the liability to them in the event of an accident), but what's the point of a driverless car that I have to pseudo-drive? Sitting at the wheel of a driverless car and not driving it sounds even more boring than actually piloting my automobile through Washington traffic.

One way to resolve this issue is to change the liability system, and funnily enough, I offered a modest proposal to do just that. But that is a big challenge, and I recognize that it is somewhat utopian.

Another way is to say that we're not going to have truly driverless cars -- at least, not for quite a while. Instead, the driverless features will be used to radically reduce the risk of accidents while still keeping people at the wheel. There's some worry that such features could cause a rebound effect -- insist all you want that drivers have to stay attentive at all times, and they'll still give in to the temptation to read their e-mail. But it's certainly a plausible argument, and it may be where we end up. Which would still be a pretty great place, because auto accidents currently kill tens of thousands of people every year.

Google Inc., however, has decided on a third approach: Slow the car down.

In an interview at Google's headquarters here, Sergey Brin, a Google co-founder who is actively involved in the research program, said the company decided to change the car project more than a year ago after an experiment in which Google employees used autonomous vehicles for their normal commutes to work.

There were no crashes. But Google engineers realized that asking a human passenger -- who could be reading or daydreaming or even sleeping -- to take over in an emergency won't work.

"We saw stuff that made us a little nervous," said Christopher Urmson, a former Carnegie Mellon University roboticist who directs the car project at Google.

The vehicles will have electronic sensors that can see about 600 feet in all directions. Despite that, they will have rearview mirrors because they are required by California's vehicle code, Dr. Urmson said. The front of the car will be made from a foamlike material in case the computer fails and it hits a pedestrian. It looks like a little bubble car from the future, streamlined to run by itself -- a big change from the boxy Lexus SUV Google has been retrofitting the last few years with self-driving technology. ...

Google's prototype for its new cars will limit them to a top speed of 25 miles per hour. The cars are intended for driving in urban and suburban settings, not on highways. The low speed will probably keep the cars out of more restrictive regulatory categories for vehicles, giving them more design flexibility.

Google is having 100 cars built by a manufacturer in the Detroit area, which it declined to name. Nor would it say how much the prototype vehicles cost. They will have a range of about 100 miles, powered by an electric motor that is roughly equivalent to the one used by Fiat's 500e, Dr. Urmson said. They should be road-ready by early next year, Google said.

Essentially, Google is building a driverless golf cart, not a driverless car. With a top speed of 25 mph -- therefore making collisions less likely to be fatal -- there's less risk that your vehicle will hurt someone if something goes wrong.

There's a lot to like about this approach. Of course, it means you lose some speed. On the other hand, most commutes aren't that speedy. And I think many people would rather have a 45-minute commute during which they can read than a 35-minute commute during which they have to listen to talk radio while white-knuckling the steering wheel and silently wishing elaborately horrible deaths on the drivers around them.

It also offers Google a way to prove the concept at relatively low risk. As the technology gets safer and more widely accepted, it can be scaled up and speeded up. If you want to get to a truly driverless future, this ultimately seems like a better bet than trying to build from a "mostly driverless" car. The transition from mostly driverless to fully driverless seems big and scary, compared with the transition from 25 mph to 30 mph ... to 35 mph ... to 40 mph ... and so on.

That said, there are two pretty big hurdles. The first is market adoption: Who will gamble on a low-speed driverless buggy? City dwellers like me, perhaps. The car's 100-mile range, presumably enabled by its lower speed, is plenty for even a long day of driving around Washington, and I'd be thrilled to swap out the Mini for something that I don't have to steer. But like many city dwellers, I don't have anywhere to charge my electrocart.

The second is that incremental speed enhancement. The 25-mph speed is dictated by a regulatory threshold; try to take your car to 45 mph, and suddenly you're in a different regulatory class, with higher safety standards (read: a lot more weight on the car) and various other requirements. So while in theory it's easy to start slow and incrementally improve, in practice, Google is eventually going to have to get regulators to let it push beyond the current limitations. That's by no means impossible, especially if the slower vehicles are widespread and widely liked. But it's going to take a lot of lobbying and time.

That said, this makes me more optimistic than I was about our driverless future. It's clear that Google is still able to find surprising, smart solutions to difficult problems -- even, maybe, to ones I think are unsolvable.

This column does not necessarily reflect the opinion of Bloomberg View's editorial board or Bloomberg LP, its owners and investors.

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Megan McArdle at

To contact the editor on this story:
Brooke Sample at