The least expensive way that privately maintained roads can be kept up is for the property owners served by the road to contribute their fair share to the annual maintenance of the road. This requires voluntary contributions from each road user which, unfortunately, are not always forthcoming.
Sometimes a user of a private road will refuse to pay his or her share of the road maintenance. The other users of the road are then forced to sue the non-paying road user in order to collect a fair share of the road maintenance cost. Private maintenance requires volunteer effort and cooperation and is usually a binding agreement. An agreement that allows establishment of property lien rights for fee collection is important. Usually, a legal entity, such as a non-profit, road maintenance association, involving all affected property owners, is necessary.
You should seek the advice of legal counsel before forming such an entity and for the review of the maintenance agreement.