The Hills Have Eyes (1977)

While traveling in a trailer through the desert to California, the retired detective Big Bob Carter stops in an isolated gas station with his family for fueling and rest. When they leave the gas station, the owner advises Bob to stay in the main road. However, the stubborn driver takes a shortcut through a nuclear testing site and wrecks his station wagon. With the family stranded in the middle of nowhere, Bob and Doug walk on the road trying to find some help. Bob is captured by an insane and sadistic member of a deranged evil family that lives nearby the spot. Later that night the Carter family is attacked by a group of psychotic cannibal criminals. Absolutely trapped by the murderers, they have to fight to survive.

IMDb: https://www.imdb.com/title/tt0077681