The Hills Have Eyes.

Even now this is a total classic of horror. The absolute best out a million bland break down and get attacked by lunatics films.

In this instance a family on the way to California, a family has the misfortune to have their car break down in an area closed to the public, and inhabited by violent savages ready to attack. In this case the family find they are lined up to be lunch for the clan of deformed cannibals in the surrounding hills.

Sadly some fool had to remake this and did a piss poor job in 2006, the original is in most instances the best and in my view should be left alone by directors who lack the talent to create something as good themselves.

A classic gore fest that has stood the test of time and is one every fan of horror should own. 
http://uk.imdb.com/title/tt0077681/
http://en.wikipedia.org/wiki/The_Hills_Have_Eyes_%281977_film%29
An old man named Fred (John Steadman) is packing his truck. A ragged and somewhat feral teenage girl approaches. Annoyed, Fred addresses her as Ruby. She offers to trade what she has in her bag for food, but the old man refuses. They walk into a small cabin and Fred scolds her for what she and "they" have done. Ruby says that her family ambushed a nearby airfield because they were hungry and no one passes by their home anymore. She pleads with Fred to take her with him. He tells Ruby that if "the pack", in particular someone named Jupiter, learns what she is doing, she could be in danger. A noise distracts them, and Ruby hides.
The Carter family is traveling on vacation. Parents Bob (Russ Grieve) and Ethel (Virginia Vincent) are driving, accompanied by their teenage children Bobby (Robert Houston) and Brenda (Susan Lanier), eldest daughter Lynn (Dee Wallace), along with Lynn's husband Doug (Martin Speer), baby daughter Katie, and their dogs, Beauty and Beast. They stop at Fred's Oasis for fuel. Fred tells them to stay on the main road. Later, they skid off a desert road and crash, owing to what is later revealed to be a booby trap. Bob walks back to Fred's Oasis to get help. Fred's son and his son's family of deranged cannibals dwell in the wilderness through which the Carters are traveling. They are commanded by Papa Jupiter (James Whitworth), patriarch of the clan. He killed his mother, Fred's wife, during childbirth. As a child, he killed the livestock on his father's farm and later murdered his sister. Fred attacked his son with a tire iron and left him in the wilderness to die. Jupiter survived, and mated with a depraved, alcoholic prostitute known as Mama (Cordy Clark). Together, they had three sons, Mars (Lance Gordon), Pluto (Michael Berryman) and Mercury (Arthur King), and their abused daughter Ruby (Janis Blythe). They survive by stealing from and cannibalizing travelers.