[xorcist]

> The roads are free at the point of use, the tube isn't.

Perhaps it should. Surely it must have been tried somewhere?

[jiggy2011]

The tube is already very busy without people using it for frivolous journeys. At least it still costs people money (car) or physical effort (cycling) to use the roads.

There are cities with free transit systems however.

http://en.wikipedia.org/wiki/Free_public_transport

[stuaxo]

In Budapest it seems to be free on the weekend, and I'm sure other cities too.