Evolutionary progress and artificial intelligence made the car territorial.
The people had wanted more done for them,driving,having to think was such an inconvenience,when all they wanted to do was gossip and compare their achievements with those of others
Google had been at the forefront of autonomous cars ,but it was a rogue operator who introduced the virus to the AI software ,all the developers had approved and were working internationally on.
Without being aware of it,cars had begun to act like scent marking animals.Driveways became their own,certain lampposts and parking places were solely for their use.
All cars were affected,and in the open Countryside,it was perhaps not such a problem.Farmers and farm workers were surprised when their vehicle stopped and sprayed water from the radiator or sometimes from the window cleaning water jets.Sometimes a spot of oil would seep from the axle.
The farmers began to notice a pattern and favoured places were regularly marked by different vehicles from different farms. The farmers quickly realized that there was a form of communication going on.

Vehicles would disappear and be found in groups near a favoured spot.It was obvious they’d had a sort of informal meet.There were tyre markings all over the place.Some of the cars were damaged as if they’d had a scuffle.Farmers began to demobilize their vehicles to stop them from running amok.
In the city and suburbs though it was a disaster.

The cars began piling up and blocking roads,there was total carnage everywhere,no one could get on the motorways to go anywhere.Indeed no one could go anywhere because all of the vehicles became totally uncontrollable.
The virus had spread to all the vehicles and the only safe method of travel became bicycles,but it was too late.The damage had been done.Everything stopped and the realisation came that there was going to be no quick solution.