Rest Stop

What a waste of 90 minutes of my life. I mean, I've seen worse movies--recently--but really! I have no problem with an "unexplained" monster villain (who is only vaguely a monster) but... some plausibility, please!
I knew it was going to be bad as soon as the old man in the RV started spouting off made-up Bible verses (and I mean OBVIOUSLY made-up; not even close to anything in the Bible). Then there was the scene where the villain pumped about a quart of gasoline through the window-grill of a rest station built entirely of cinder-blocks and threw a lighter through the window (which the heroine, seeing it coming and holding in her hands a wastebasket much larger than the window, made no attempt to block), thereby causing the rest station to explode.
I won't even start with the dying cop's radio and gun!!!