1) So you can't have contracts like that? Contracts that says that you can change the rules by majority vote. Or implicit contracts. Or "the spirit of the law" as somebody called it.
2) Who needs to stop it completely? I just need do disrupt it. And who's to say I can't make money out of that. I could have patches of land outside of the city that I'd want to increase the value of. Or have environmentalists pay me to plant trees there. And to build new roads, even if you find place, you still have to convince every single homeowner that they want a new road on their doorstep. A single "no" would stop any improvement efforts on your part.
1) Sure, you can. There's an implied contract between you and the owner of a restaurant and yourself, that he will feed you, and you will not be an asshole. And you can have contracts where the rules can be changed by majority, but not combined at the same time. Especially when you are given no choice to accept or not the implied contract. If all your neighbors wrote up a contract that said you were the town sperm dumpster, and had to perform fellatio for any and all of them, would you feel like you have accepted a fair contract?
2) As I said, the landowners which surround your roads will not sell, they'll get together and build a road themselves, to capture some of that business that you're rejecting, if not simply to make life easier for themselves. As to making money by doing that, I suppose you could, if you wanted to ruin your reputation. You could probably make much more money by running the roads so as to maximize traffic, and as a bonus, you don't piss off an entire city.