Legal Question in Real Estate Law in California

If there is a deeded easement, he cannot prevent you from using the road for the purpose shown in the easement (usually ingress and egress). It may also allow utilities. Not sure where the gate is that you are talking about. If it is on your property, he has no control of that. However, you cannot put a fence in the easement area.

Yours is a very complicated question that cannot be answered without reviewing the relevant title documents and the exact location and history of the use of the access road. There is no way to tell from your question who has what legal rights in the road. You are right that it is possible for people to acquire a private or public easement over your road if you don't take steps to stop them for a long enough time, but there are very strict rules as to how and when that can happen. There is no way to tell if the situation fits those rules from your question.

A "deeded access road" does not fully describe a unique legal situation. Deeds can convey all kinds of rights, including, for example, (1) exclusive ownership in fee simple absolute; (2) co-ownership as a tenant in common with the other two properties; or (3) an easement for ingress and egress. There are other possibilities as well.

Easements can be created by express grant or reservation in a deed, by prescriptive use over a period of five or more years, and in several other ways. They can also be modified or extinguished in several ways.

The holder(s) of an easement have rights to use the easement for the purpose(s) for which it was created, and the owner of the underlying land may not unduly interfere with the use of the easement. The landowner sometimes can put a gate across a road easement, if reasonably necessary to keep his livestock in or other folks' livestock out (for example), but must give the easement holders keys. In other situations, the court may rule that the gate is an unnecessary interference with the easement holders' rights.

If the gate in question is lateral to the roadway and would allow you as an abutting landowner to enter the roadway from your parcel and vice-versa, I suppose the right to install and use the gate is dependent upon your right, if any, to use the road itself.

Now, just a word about prescriptive easements. A simple example is that if I trespass across a corner of your front yard to and from my curbside mailbox regularly for five years, without your permission, you may (and probably will) lose the power to deny my use of the short-cut, and I could even go to court and get a judgment giving me (and my successors) an easement for that purpose. That wouldn't make me the owner of the land, nor would it give members of the public who don't live on my land any rights to use the easement.