Lots of psychological underpinnings...
***SPOILERS AHEAD***
Sure, Duel is a film about a man being chased by a large truck. It is in a way nothing more than a 90 minute long car chase.
That's how I saw it the first time I watched this movie, which would have been in the early 80's, and I was maybe 8 or 9 years old. I loved it then, and have continued to love it growing up, but for different reasons.
After deconstructing the entire film while writing an essay about it, I came to the conclusion that the truck (and it's obscured driver) is more on the lines of a representation of David Mann's fear of conflict. The truck manifests itself every time David is reminded of- or brought back to that fear...
In the beginning David is cruising through the empty landscape, enjoying his time away from home (the fact that he has problems at home - being pretty much bullied by his wife and his colleagues - becomes very clear later on in the film). He's listening to the radio, laughing at the talk-show program.
The radio host is talking about a census report that has been sent out to the general public, to make some sort of statistic documentation of income and family status (I'm guessing, judging from what he's saying).
Mann laughs away...
The radio host makes a prank call to the census bureau, claiming to be one of the census takers, asking silly questions.
Mann continues to laugh...
When the radio host says something like "Here it says; Are you the head of the family? What am I supposed to answer there? I mean sure I make the money - but ever since I married that woman, 25 years ago, I lost the position as head of the family." The jokes continue to run in this direction, while Mann's laughing becomes less and less prominent.
-THEN the truck shows up!
He is stuck behind this stinking vehicle for quite a while, and just as the radio host takes his prank call to a ridiculous level - claiming to wear a dress/skirt at home - he manages to drive past the truck... But as soon as the joke is taken back to a more believable level he is overtaken.
Every time he is in a position where he is reminded of things that causes conflict or things/situations where he is being put down without speaking up or fighting back, the truck shows up.
It waits patiently outside the gas station as he is scalded by his wife on the phone, and starts to pursue him more frenetically right after that.
When he arrives at the diner the truck drives on and disappears, but after a quick visit to the bathroom - during which he talks about being "taken right back to the jungle again" (the Vietnam war, I'm guessing) - he finds the truck sitting outside on the road when he comes out to the restaurant.
As soon as he musters up enough courage to confront the one he thinks owns the truck (he is of course wrong and gets his ass kicked, but still - he did face his fear and enter into a conflict) the truck starts it's engine and drives away.
The school kids taunting him and the school bus driver not listening to him - there's the truck again.
Trying to avoid conflict by calling the police - truck forces him to deal with the situation.
Near the end, when David tries to WALK up to the truck, it avoids him, drawing a symbolic line between David's car and Davids old self and his old life. As if it's saying "If you want to face me, you're gonna have to face yourself too."
So David get's inside his car, fastens his seat belt and slowly nears the truck. The driver holds his hand out the window and waves at him to drive on... This is my favorite part of the whole film. With this simple gesture he's saying "This is the point of no return. You wanna fight? You wanna be a real man? Do you want to face you fears...? Go."
The chase is endless, and David's car (his old self) gets more and more smashed up. It overheats, it careens wildly downhill, it runs within a few millimeters of getting out of his control.
He crashes it into the side of a cliff...
Now, had David continued to be the chased, meaning had he continued to run away from conflict, he would most likely have been consumed by it - gotten killed. But when he finally decides he's had enough, and turns his car/life around to face the truck/conflict he is released.
He even places part of himself "behind the wheel" as it were, as we do see in a very clear zoom shot how he puts his briefcase, marked David Mann, on the pedal of the car to keep it running.
He bails out of his old life and watches as it catches fire and get's smashed to a million pieces.
-Elation follows....
I know, I know.
I've gone on far too long.
This movie just brings this out in me. :)
"Racoon, Rog?"