On Sun, 10 Jun 2007 14:23:04 +0100, Tony Raven
wrote:

[blanket 20mph]
Why not?

Because people need to get places more quickly than that, and unless
you have an entirely segregated rapid transit rail system in every
city to fulfil that role at least the buses will need to do so, even
if you take the view that you want to make car use so inconvenient
that nobody will want to bother.

Neil

--
Neil Williams
Put my first name before the at to reply.