Does anyone know the movie about . . ?

I don't know the full movie , but basically at the end of the movie , this man kills his kids and his wife . And there in a car and it is all misty and foggy around the car . I think there were other people in the car that he shot , but i dont remember. And I think he was gonna kill himself but he gets out of the car and he's see a truck's headlight . . And he is like screaming . I think he kills them because the world was supposed to end . Ughh i really wanna watch the movie again . Please I hope someone knows and this happened at the end of the movie .