Terror Trap (1969) on Netflix

While driving at night on a lonely road, the car of estranged couple Don and Nancy is hit twice by another car in the middle of nowhere. Nancy asks for help and unpleasant sheriff Cleveland offers to take them to the nearby Motel Royal Vista and wait until the morning, when their car would be towed. When the couple arrives in the low-budget motel, they are attended by a weird receptionist. They are disturbed by noises and screams from inside the next room and Don asks them to keep quiet since his wife and he are tired and need to rest. But soon they realize that they are part of a sick and deadly game, and their lives are threatened.