In the US (at least in California at any rate) they have carpool lanes, in which you can only drive if there is more than one person in the car. This is California's version of public transport.
A woman was recently pulled up by the highway patrol for driving alone in a carpool lane. She replied that she was pregnant, and therefore there were two people in the car. This of course opens up a huge can of worms.
The woman is actually (at the moment) expected to win her case. This of course does not worry the ever resourceful California Highway patrol, as they can then prosecute her under an obscure law that forbids more than one person sitting on the driver's seat of a car...