And, this tends to open up another can of worms and an argument that no side will every concede ground on.
Depending on whose figures you believe, road taxes (as part of rego), fuel taxes etc either cover the roads budget or they don't. According to figures I obtained when I was involved in bicycle advocacy: in NSW (I assume Qld Is worse off because of less tax / longer roads), the total raised (including NSW share of federal money) falls well short of the amount spend on road building / maintenance.
Then there are the social costs of motoring: pollution, road trauma, sedentary lifestyles etc and the $billions they can cost to society.
I think, the last thing the average motorist would want, is to be asked to pay the true cost of motoring.
As for your point about waste in other spending areas.
All spending is wasteful unless it benefits us or we sympathize with those it benefits. I used to drive a Yellow Cab around Brisbane. The taxi subsidy give to disabled people was constantly attacked by the shock jocks as wasteful. To others, it is the most sensible spending in government history.
Scotty