Free exchange: Jam tomorrow 自由交流：堵在明天

　　Driverless cars will not save cities from either traffic or infrastructure expense. 无人车不会将城市从滚滚的车流和基础设施耗费钱财中拯救出来。

　　The most distractingly unrealistic feature of most science fiction—by some margin—is how the great soaring cities of the future never seem to struggle with traffic. 大多数科幻小说的最令人想入非非的不现实的情节——大约要算是——未来的大城市似乎从来不怎么与滚滚车流作斗争。

　　Whatever dystopias lie ahead, futurists seem confident we can sort out congestion. 不管摆在前方的乌托邦到底如何，未来主义者似乎对我们能够消除拥堵充满信心。

　　If hope that technology will fix traffic springs eternal, history suggests something different. 如果说技术将调度滚滚车流的希望生生不息的话，历史告诉人们的则是不一样的故事。

　　Transport innovation, from railways to cars, reshaped cities and drove economic advance. 从铁路到汽车的交通运输创新重塑了城市，推动了经济的发展。

　　But it also brought crowded commutes. 但是也带来了通勤拥堵。

　　Now, as tech firms and carmakers aim to roll out fleets of driverless cars, it is worth asking: might this time be different? 现在，当科技公司和汽车制造商旨在推出大量的无人驾驶汽车的时候，我们有必要问：这一次会不同吗？

　　Alas, artificial intelligence (AI) is unlikely to succeed where steel rails and internal-combustion engines failed. 唉，在铁轨和内燃机发动机都失败的地方，人工智能是不大可能获得成功的。

　　More’s the pity. 真是太可惜了。

　　In America alone, traffic congestion brings economic losses estimated in the hundreds of billions of dollars each year. 单是在美国，交通拥堵带来的经济损失每年估计在上千亿美元。

　　Such costs will rise unless existing transport systems receive badly needed investment. 除非现有的运输系统收到了迫切需要的投资，这样的代价将会提高。

　　For example, fixing New York’s beleaguered, over crowded subway will take at least $100bn, according to one recent estimate. 例如，根据一项最近的估计，维修纽约存在诸多问题并且过度拥挤的地铁，将会花费至少1000亿美元。

　　A driverless deus ex machinamight seem to spare governments some difficult decisions. 一个无人驾驶的解围之神可能会让政府免于做出一些艰难的决定。

　　But congestion is a near-inevitable side-effect of urban growth. 但是，拥堵是城市发展的一个不可避免的副作用。

　　Cities exist because being near to other people brings enormous advantages. 城市存在的原因是与挨着其他人带来了极大的优势。

　　Proximity allows people to find friends, mates and business partners, to discuss ideas and generate new ones, and to trade (and so to capture the benefits of specialisation). 近距离可以让人们找到朋友、伴侣和商业伙伴，去讨论想法、产生新的想法，并且进行交易（进而可以得到特殊化的福利）。