After the truck and Amy leave, Jeff finds an electrical cable loose. When he gets to Belle's Diner, Jeff discovers that nobody has seen his wife. What the film does very well is to put us inside Jeff's skin. A couple of things make this movie work as well as it does. Jonathan Mostow's direction and the screenplay by Mostow and Sam Montgomery are very lean.
Every scene advances the narrative or builds character.
In Breakdown, there are just two minor violations of camera truth, where the bad guys are alone with Jeff and lie to him when they don't have to. But the filmmakers can easily offer an alibi for this. They can claim it's all a matter of the bad guys acting out sheer sadism, twisting the knife in Jeff a little longer. Jeff is a well-written character, and Russell plays him with intelligence and empathy. Furthermore, the filmmakers have no interest in pursuing what to others might have seemed the obvious.