You jump into a car, tell it where you want to go, then sit back and let a computer take control. It seems like a dream in the future. It isn't.

跳进汽车，告诉它你的目的地，然后，你就可以往后一坐，让计算机操控车辆。这听起来像一场未来的梦。然而，这并非梦。

In many ways such driverless cars are already　with us. There is partial automation in many cars，such as intelligent braking, lane departure warning and automatic parking. The systems are there so that cars can pretty much drive themselves. No one noticed the introduction of cruise control. We've got collision avoidance, and we'll soon have automatic lane change.

在许多方面，这种无人驾驶的汽车已经存在。许多车已经有了部分自动功能，比如智能刹车系统、车道偏离警报系统、自动泊车系统。安装了这些系统，车辆完全可以自行驾驶。安装的定速巡航常被人们忽视不用。我们已经有了防撞系统，很快，我们还将会有自动换道控制系统。

Improving this technology should make the roads safer. Machines are much better at following rules than humans. Road signs ad vise drivers to slow down to avoid creating jams. They are often ignored by drivers. But it won't happen to a computer. Driverless cars could also choose the best route to avoid traffic jams.

改善这种技术能够让道路更安全。机器比人类更擅长遵守规则。路标建议司机减速以避免导致堵塞，但常常被司机视而不见。但对于计算机来说这是不可能发生的。无人驾驶汽车还可以选择最佳路线以避免交通堵塞。

Fewer jams will mean less stop-start driving. Maintaining smooth and constant speeds will improve fuel efficiency. Computers could also be programmed to take the greenest route, rather than the fastest one. Under computer control, cars could also travel much closer together.

更少的堵塞意味着驾车时更少的启停。保持匀速行驶可以提高燃油效能。电脑可以设定程序，选择最绿色环保、而不是最快捷的路线。通过计算机控制，车间距可以更短。

They can effectively “slipstream” one another and use less fuel to move themselves forward. They can even form multi-car “trains” going at high speeds. However, with driverless cars on the roads, there will be potential trust issues between people and machines. We could therefore see guard rails back on the sides of roads. This would be a backward step.

它们可以有效地在前面车辆形成的滑流里行驶，这样可以使用更少的燃料驱动车辆自身前进。他们甚至可以像火车一样，多车连在一起，高速行驶。然而，在道路上使用无人驾驶汽车，人和机器的信任问题需要解决。因此，可能在路的两边需要安装护栏，这无疑是一种倒退。