I still don't believe that these taxes -although well intentioned- let us know whether vehicle owners want and are prepared to pay for that road. If we made the tyre tax an optional extra then they have the choice, but forcing the tax upon them is coercive.
What you are suggesting, however, is that people have the two different options: pay the tax or don't pay the tax, and whether they choose to pay or not is independent of the service/product they receive. Most people will not choose to pay out in this manner, because if the road gets built they get to use it anyway. Ever hear the story of the Little Red Hen? None of the other animals wanted to help the Little Red Hen gather the ingredients, prepare the dough, or make her bread, but when it was done they were more than happy to help her eat it. This is human nature.
Connecting the analogy back to healthcare for a moment, there are even ways to have a direct tax to help pay for the system. Look at Canada; Canadians will occassionally rave about how cheap cigarettes are here. The reason why is that even with all of the "oppressive" taxes that our government has placed on cigarettes, we're still about half as expensive as Canada. The reason why this system works for Canada is that smoking is a high risk habit which contributes to health problems, so directly taxing those who smoke means that those who contribute to the problems are helping pay for them. We do the same thing for other "high risk" behaviors here. Why do you think you get a ticket for not wearing a seatbelt or a motorcycle helmet?
This is the logical disconnect with the left's argument, I'm told that society wants and needs state services, but I'm also told that we all need to be forced into making payments because is given the choice we wouldn't pay up. It sounds like they want it both ways.
People just don't want to be the ones left holding the check. They want some assurance that others will contribute their fair share rather than not paying in and reaping the benefits. (See the Little Red Hen story).
There is a good compromise solution I've seen before that is available when the tax is suggested in election season: putting the question on the ballot. "Do you think that the sales tax should be increased by 1% in order to help pay for X project?" People get to have their say and express their priorities. Additionally, those who think it would be a good idea, but would only go for it if everyone would be contributing equally have some assurance that this would be the case. Everyone gets to express their opinions, and even if not everyone gets exactly what they want, the public as a whole does.