Because the amount of wear
that a bicycle does to road is infinitesimal compared to that done by a car.
And because a significant amount of road tax money (most?) is spent on buiding and maintaining motorways, which cyclists aren't allowed on.
( Newington, Wed 11 Aug 2004, 11:35, archived)

Cyclists should, however, be forced to have numberplates
At the moment they (we) can flagrantly break the law and easily get away with it. Cars etc can be tracked by their registrations, which can easily be picked up on traffic cameras. It should be the same for bikes.
( TV's Nosemonkey, Wed 11 Aug 2004, 11:41, archived)

That's not a bad idea.
I doubt anything'd be enforced though. Round here they won't stop you for cycling on the pavement or without lights.
( Newington, Wed 11 Aug 2004, 11:49, archived)

... but at least you'd be able to report the tossers who cause accidents...

( Beastie is doing science with his arse, Wed 11 Aug 2004, 11:54, archived)

I know it's heavier than a pushbike...
but my 500cc motorcycle has a taxation class of "bicycle"...

Doesn't count as one for parking etc though...
( Beastie is doing science with his arse, Wed 11 Aug 2004, 11:48, archived)