Necessity and Permissive Easements
The courts will find an "easement by necessity" if two parcels are so situated that an easement over one parcel of land is strictly necessary to the use and enjoyment of the other parcel of land. The creation of this sort of easement requires that at one time, both parcels of land were either joined as one or were owned by the same owner. Prior use of the easement, however, is not required. The most common example of an easement by necessity is landlocked property, so that access to a public road can only be gained by having a right of way over an adjoining parcel of land. The legal theory is that the landlocked parcel was accidentally created, and the land owner forgot to include an easement or method of access to reach the road.
A permissive easement is simply permission to use the land of another. It is essentially a license, which is fully revocable at any time by the property owner. In order to be completely certain that a permissive easement will not morph into a prescriptive easement, some landowners erect signs stating the grant of the permissive easement or license. Such signs -- often found on private roadways -- typically state: "This is a private roadway. Use of this road is permissive and may be revoked at any time by the owner."