Driverless cars used to be the sort of thing you'd see in sci-fi films，but in 2020 they're becoming a reality．Autonomous car technology is already being developed by the likes of Lexus，BMW and Mercedes，and we've even tested Tesla's driverless Autopilot system on UK roads．Across the Atlantic，Google is developing its automated technology in the wild，and Apple is rumoured to be working with BMW on its own-probably automated-car．
    Fully-driverless tech is still at an advanced testing stage，but partially automated technology has been around for the last few years．Executive saloons like the BMW 7 Series feature automated parking，and can even be controlled remotely．
    With so much investment and interest in driverless technology，it's easy to assume that self-operating cars are likely to happen soon，but they're much further away than we might think．Before diverless vehicles go to market widely，manufacturers must deal with a range of technical and ethical challenges，and prevent the biggest threat to autonomous technology：humans．
    The human problem
    Humans present problems for autonomous cars as both drivers and pedestrians，and dealing with our unpredictable behaviour represents a significant challenge for the technology．
    The Google Car is one of the most experienced autonomous vehicles．Even so，its interaction with human drivers has given rise to the exposure of one of driverless cars' main weaknesses．The first injury involving the Google Car wasn't due to a fault in its system，but human-error．While correctly waiting at traffic lights，Google's self-driving car was hit by an inattentive driver and，in spite of its sophisticated array（復(fù)雜精密的數(shù)組） of sensors，there was little it could do to avoid the incident．Luckily，the accident only resulted in minor injury for a few of the passengers，but it's a reminder that autonomous cars are at risk when surrounded by human road users．
    Despite their sophisticated systems，self-driving cars currently have no plan B for human road users．Human drivers are able to interact with each other and make allowances，but also make countless，small mistakes when driving-mistakes to which current self-driving cars simply can't adapt．
    Dealing with pedestrians
    The way human drivers interact with pedestrians raises difficult moral and ethical questions for car manufacturers-with implications．
    Autonomous cars need to understand the way pedestrians behave，while also imitating the behaviour they'd expect from a human driver． "Everyone has a knowledge of how a human being is going to react，because we are all human beings，" says computer ethics commentator Ben Byford． "So if you walk out in front of a car，and presumably the car driver knows you're there，they're going to react in a certain way．"
    "If I walked out in front of a Google car travelling at 60 mph，I have no real knowledge of how the vehicle will behave，so I'm effectively putting myself in danger．"

How （1） far far away are we from autonomous cars？
Background information	? Autonomous car technology has been （2） tested/developed tested/developed in some famous car manufacturers． ? Partially automated technology has been in （3） use/ application/existence use/ application/existence for the last few years． ? Before our roads are （4） crowded/ flooded crowded/ flooded with driverless vehicles，manufacturers have a lot of things to do．
（5） Concerns/Worries Concerns/Worries about the autonomous technology	The human problem	? The Google car's accident has （6） exposed exposed one of driverless cars' weaknesses． ? （7） Despite Despite the sophisticated array of sensors，Google's self-driving car could do little to avoid the accident． ? With no alternative plan，self-driving cars cannot have a good （8） interaction interaction with human drivers．
	Dealing with pedestrians	（9） Unlike Unlike human drivers who know pedestrians well，autonomous cars have difficulty in（10） understanding/knowing/ predicting understanding/knowing/ predicting their behavior，thus putting pedestrians in dang