Thought Experiment: Driverless automated cars
In the linked article you can read about driver less pods at Heathrow airport that take passengers from the car park to the terminal. Driver less automated pods are certainly part of the future, one day they may even replace ordinary cars on ordinary roads.
However here is a thought, a driver less pod will always be programmed to stop for a pedestrian / obstruction as the whole point in driver less pods is to prevent accidents. This all sounds very sensible and logical but what happens when pedestrians know they can never be hit by a car. Simple, they will step out into the road without looking as they know any car will stop and they cannot be hurt.
Now extend this thought, which basically means that pedestrians now have priority. In towns and cities pedestrians would reclaim the streets, traffic would be brought to a stand still and the whole fabric of society would break down. Ok maybe not that last part.
So if cars are no longer dangerous pedestrians would no longer be wary of them. You could either
a) Trust pedestrians to do the right thing - make it socially unacceptable.
b) Allow cars to be slightly dangerous again.
c) Make it a serious criminal offence to cross the road when a driver less car is coming.
d) Or another option which I haven't yet thought of.
Its an interesting thought which may have to be solved before driver less cars go mainstream.