Consult with a real estate attorney before doing anything. If there is an easement on the road--i.e. a legal right given to the owner of the property you wish to buy--then you *may* be able to make the repairs if the owner of the road/land does not after repeated requests, though it's also possible that the proper recourse is to go to court for  an order requiring him to either make the repairs or at least allow you access to repair (e.g. doing work on his land, even if there is an easement to travel over the road, without his permission could be trepassing without a court order).If there  is no formal easement existing, it may be that  one would be created by law IF the property you wish to buy is "landlocked"--that is, this road is the only way *possible* to access  it. However, if the property is not landlocked and its owner could reach a public road in some other way, it may be that you would have to pay to build your own road linking to public roads.In short, you *might* have the right to make the repair, but it depends on the facts of the situation; and even if you have the right to do this, the mere fact that  you could be dependent on others greatly complicates matters (and could reduce resalability). You need to understand this situation better before  acting.