I'd pay to use toll roads or even a pay as you drive scheme, provided this was instead of and not on top of the existing duty.
A CO2/km scaled pay as you drive system is the only fair way of taxation...
Currently a Toyota Prius doing 30k a year will be charged £0 tax, yet will stick 4200kg of CO2 into the atmosphere.
A Zed doing 3k a year, will be charged £460 tax, yet only put out 1300kg of CO2.
Obviously, this system wouldn't be good for Zed owners who do 30k a year!
A just a quick defence of lorry drivers (Of which I am neither one or particular fan of), but they are very strictly limited to the amount of time they can spend on the road before having to stop. Even a few miles an hour can make a huge difference... Although I completely agree at how annoying it is when they're taking up 2 out of 3 lanes!