In message , Bonzo
writes

I don't understand why this simple but useful tool has not been
generally introduced into the UK, especially into London, which is in
may ways so innovative.

It seems universal in many parts of the European mainland, and it
doesn't require GPS. Just a feed from the ticket machine as the driver
changes the location/stage - although I agree that GPS is even better.

Since there are now no fare stages or bus zones in London, and many
central area bus drivers don't even sell tickets any more, I'm not quite
sure how that would work.

--
Paul Terry