You can speak to a real property attorney about enforcing the agreement. For the agreement to be valid, it would need to be in writing in a contract or in the deeds granting ownership to the land. Without this, you will have a very difficult case. Further, because you know the road is damaged, the law places a duty to mitigate (minimize) your damages. You will be expected to slow down, use caution, and take other steps to limit your damages as much as possible.
Answered on Jan 21st, 2013 at 1:25 PM