Final answer:
Sam has a private easement of necessity to use his neighbor's driveway to get to the beach.
Step-by-step explanation:
The type of easement that Sam has on his neighbor's driveway to get to the beach is called a private easement of necessity. This type of easement is granted when a person has no other reasonable way to access their own property except by crossing a neighbor's land. It is based on the principle that everyone should have a reasonable means of accessing their property.