Road block

Driverless cars illustrate the limits of today’s AI

经济学人七月刊

IN MARCH Starsky Robotics, a self-driving lorry firm based in San Francisco, closed down. Stefan Seltz-Axmacher, its founder, gave several reasons for its failure. Investors’ interest was already cooling, owing to a run of poorly performing tech-sector IPOs and a recession in the trucking business. His firm’s focus on safety, he wrote, did not go down well with impatient funders, who preferred to see a steady stream of whizzy new features. But the biggest problem was that the technology was simply not up to the job. “Supervised machine learning doesn’t live up to the hype. It isn’t actual artificial intelligence akin to c-3PO [a humanoid robot from the “Star Wars” films]. It’s a sophisticated pattern-matching tool.”

Lorry：货运卡车   live up to 不辜负；做到；实践   akin to ：相似  

sophisticated /səˈfɪstɪkeɪtɪd/adj. 复杂的；精致的；久经世故的；富有经验的 v. 使变得世故；使迷惑；篡改（sophisticate的过去分词形式）

whizzy adj. /ˈwɪzi/采用先进技术的 • a whizzy new handheld computer 技术先进的新掌上电脑

hype /haɪp/n（电视、广播等中言过其实的）促销广告，促销讨论

·marketing/media hype 夸张的促销╱媒体广告

 V. ~ sth (up) ( informal disapproving ) to advertise sth a lot and exaggerate its good qualities, in order to get a lot of public attention for it 夸张地宣传（某事物）

Policing social media, detecting fraud and defeating humans at ancient games are all very well. But building a vehicle that can drive itself on ordinary roads is—along with getting computers to conduct plausible conversations—one of the grand ambitions of modern AI. Some imagined driverless cars could do away with the need for car ownership by letting people summon robotaxis at will. They believe they would be safer, too. Computers never tire, and their attention never wanders. According to the WHO, over a million people a year die in car accidents caused by fallible human drivers. Advocates hoped to cut those numbers drastically.

plausible adj. /ˈplɔːzəbl/  OPP implausible

1.( of an excuse or explanation 借口或解释 ) reasonable and likely to be true 有道理的；可信的 •Her story sounded perfectly plausible. 她的说辞听起来言之有理。

2.( disapproving ) ( of a person 人 ) good at sounding honest and sincere, especially when trying to trick people 巧言令色的；花言巧语的  •She was a plausible liar. 她是个巧言令色的说谎高手。

 do away with

1.PHRASAL VERB To do away with something means to remove it completely or put an end to it. 消除; 终结 •  The long-range goal must be to do away with nuclear weapons altogether.  长远目标一定是销毁所有的核武器。

2. PHRASAL VERB If one person does away with another, the first murders the second. If you do away with yourself, you kill yourself. 谋杀•  ...a woman whose husband had made several attempts to do away with her.  … 一位丈夫数次试图将其谋杀的女人。

summon v. /ˈsʌmən/  

1.( formal ) to order sb to appear in court 传唤，传讯（出庭）

•He was summoned to appear before the magistrates. 他被传唤在地方法院出庭。

2.~ sb (to sth) ( formal ) to order sb to come to you 召唤 •She summoned the waiter. 她召唤服务员过来。

3.[ VN ] ( formal ) to arrange an official meeting 召集，召开（会议）•to summon a meeting 召集会议

4.[ VN ] ( formal ) to call for or try to obtain sth 吁求；请求；争取 •to summon assistance/help/reinforcements 请求援助╱帮助╱增援

5.[ VN ] ~ sth (up) to make an effort to produce a particular quality in yourself, especially when you find it difficult 鼓起；振作；使出 •I couldn't even summon the energy to get out of bed. 我甚至连下床的力气都没有。

SUMMON STH UP：to make a feeling, an idea, a memory, etc. come into your mind 唤起；使想起

And they would do it soon. In 2015 Elon Musk, the boss of Tesla, an electric-car maker, predicted the arrival of “complete autonomy” by 2018. Cruise, a self-driving firm acquired by General Motors in 2016, had planned to launch self-driving taxis in San Francisco by 2019. Chris Urmson, then the boss of Waymo, a Google subsidiary widely seen as the market leader, said in 2015 that he hoped his son, then 11 years old, would never need a driving licence.

But progress has lagged. In 2018 a self-driving car being tested by Uber, a ride-hailing service, became the first to kill a pedestrian when it hit a woman pushing a bicycle across a road in Arizona. Users of Tesla’s “Autopilot” software must, despite its name, keep their hands on the wheel and their eyes on the road (several who seem to have failed to do so have been killed in crashes). The few firms that carry passengers, such as Waymo in America and WeRide in China, are geographically limited and rely on human safety drivers. Mr Urmson, who has since left Waymo, now thinks that adoption will be slower and more gradual.

Black swans and bitter lessons

Self-driving cars work in the same way as other applications of machine learning. Computers crunch huge piles of data to extract general rules about how driving works. The more data, at least in theory, the better the systems perform. Tesla’s cars continuously beam data back to headquarters, where it is used to refine the software. On top of the millions of real-world miles logged by its cars, Waymo claims to have generated well over a billion miles-worth of data using ersatz driving in virtual environments.

The problem, says Rodney Brooks, an Australian roboticist who has long been sceptical of grand self-driving promises, is deep-learning approaches are fundamentally statistical, linking inputs to outputs in ways specified by their training data. That leaves them unable to cope with what engineers call “edge cases”—unusual circumstances that are not common in those training data. Driving is full of such oddities. Some are dramatic: an escaped horse in the road, say, or a light aircraft making an emergency landing on a highway (as happened in Canada in April). Most are trivial, such as a man running out in a chicken suit. Human drivers usually deal with them without thinking. But machines struggle.

trivial adj. /ˈtrɪviəl/  not important or serious; not worth considering 不重要的；琐碎的；微不足道的 • a trivial detail 细枝末节

One study, for instance, found that computer-vision systems were thrown when snow partly obscured lane markings. Another found that a handful of stickers could cause a car to mis-identify a “stop” sign as one showing a speed limit of 45mph（miles per hour）. Even unobscured objects can baffle computers when seen in unusual orientations: in one paper a motorbike was classified as a parachute or a bobsled. Fixing such issues has proved extremely difficult, says Mr Seltz-Axmacher. “A lot of people thought that filling in the last 10% would be harder than the first 90%”, he says. “But not that it would be ten thousand times harder.”

obscured /əb'skjuəd/v. 隐藏，遮蔽；（使）费解；（使）相形见绌（obscure 的过去式及过去分词）adj. 遮蔽的，湮没的

baffle /ˈbæfl/ V、to confuse sb completely; to be too difficult or strange for sb to understand or explain 使困惑；难住N、（控制声、光、液体等流动的）隔板，挡板，反射板

parachute /ˈpærəʃuːt/N、降落伞；V、跳伞、空投

 bobsled/'bɒbsled/ n. 双人（或四人）大雪橇；雪橇；雪橇比赛（等于 bobsleigh）v. 滑大雪橇；乘大雪橇（同 bobsleigh）