American Perfekt (1997)

Criminal psychiatrist Jake Nyman is taking a much needed vacation from responsibility with an experimental road trip during which every decision will be made on a flip of a coin. Meanwhile Sandra Thomas, disenchanted professional, is en route to pick up her flunked out sister, Alice, at a cheap motel before continuing on to visit their ailing mother. After being forced off the road by a mysterious assailant however, Sandra is picked up by Jake, whose coin flipping amoral attitude quickly excites her own desire to break a few rules. Or worse. Jake and Sandra's romance is soon driven by chance acts of crime and kindness, all governed by the flip of a coin - at least until Sandra mysteriously disappears and Jake unwittingly picks up her suspicious sister, Alice ...