Private Access Easement
A property owner may sell an access easement to a neighbor for a driveway or path, so that the neighbor can have access to her own property. This is a private easement and not mandated by any government authority. This easement must be given in writing, and it becomes a permanent part of the title to the property, which subsequent owners must honor.
Legal Access Easement
A property owner cannot prohibit a neighbor from having access to his property. If a dispute arises, the neighbor may acquire a legal easement, granted by the municipality, county or state agency overseeing local property rights. That easement will allow for a driveway or path so that the neighbor can access his property. This easement becomes permanent and remains a part of the easement giver's property title.
The government has the right to eminent domain---the seizing of private property for public use. The government entity involved may be a federal, state, county or municipal agency. The property owner must grant an easement to create a public road where the government deems it necessary. In some cases, the property owner may be paid fair market value for the strip of land involved in making the road. The width of the road is at the discretion of the government.
A property owner may grant or sell the right to a private road across her property. That road would be used for the neighbor's travel. The easement would not give anyone the right to park, mow or use the road area for any purpose other than transportation. The property owner may put up a gate, as long as the neighbor has the ability to pass through the gate. The neighbor's guests must also be allowed to use the road once an easement is granted.