Re: Why should the car be 'slow to respond'
Another aspect of this is in the UK, the speed limit isn't the speed you should be driving at, it is simply the maximum speed you may drive at, because at all times you should drive at a speed appropriate to the conditions. If the police decide that your speed was inappropriate then they can charge you...
Thus a big issue is going to be driving in poor weather: the systems in a autonomous vehicle might work in fog and thus permit a vehicle to travel at 60mph when visibility is sub 10 metres, however, this may not be safe because other road users (eg. pedestrians, horse riders etc.) are relying on the human eye.