I think it's deceptively easy to assume the whole film is about Bruno. The liner notes spend a bit more time on him, but to me Roberto moves the film so well. Roberto does not need to invite him up at the film's start, but Roberto is the one inviting Bruno into his life. Roberto faces the conflict which is quietly revealed, that he knows he's different and he knows he doesn't fit in. In a way, he is using Bruno to get what he wants. Bruno might be driving, but Roberto is the navigator.
It's as if we're asked, what would Roberto's life be like if he ended up like Bruno? And he sees the pros and cons of that throughout the film. Lucky with women, but overall, perhaps unfulfilled like life. (My wife pointed out to me that the color red and peppers are both signs of luck in Italy, something the liner notes don't seem to touch on ((I haven't gotten through the bonus features)).) So the irony of Roberto is that he thinks he can just turn off his brain, stop worrying so much, get a little drunk, and voila, he's Bruno. But it's not that simple. Bruno, after all, is the one with the pepper in his car. He's obviously had enough luck just to stay alive at this point in his life. Roberto might not be so blessed. We know that, because Roberto's father wasn't blessed. His uncle reveals that he showed promise as a young lad, but clearly never lived up to that promise. Roberto, on the other hand, has defied his nature by chasing after something honorable: a law degree. He's not following in his father's footsteps, which is good. But to find out what it could be like if he had, we have a bit of a taste of it by seeing him with Bruno. The successful influence of his uncle's castle gave Roberto something to aspire to as a boy. And it's what he's chasing. Though probably not having fun doing it. As he sees, if he's successful, he'll have a Fiat 1500 and a doting wife who blindly agrees with everything he says (like his cousin has), and this he doesn't want. He also scoffs at the overpriced food in the last restaurant they visit. If he hates these things, why is he chasing after them?
Of course, Bruno does, to a degree, steal the show. His swagger, charisma, and personality, leap off the screen. You could write a whole post just on the ridiculous contradictions he makes, but my absolute favorite had to be when he yells at the bikers he drives by. He tells the biker that he should "get a Vespa." And then the next person they pass is ON a Vespa, and he says, "Eat my dust, slowpokes!" He loves, then hates the country. He loves cars, but he hates machines (cigarette machine). And while he comes off shrill and arrogant, he constantly shows how wise he is. He realizes that his cousin is really the son of one of the workers of the house. And he's not blind to his own problems either. He warns Roberto that he can call that girl he's in love with, or end up a "stray dog" like him. It's not so fun being single at his age.
There are two big motifs in the film for me: 1) the chase and 2) momentum. Both men are all about the chase. If you are not chasing something, you are being passed. When they get passed, life is difficult. It is essential that if you are chased, you don't get caught. With that said, being caught is not fatal (I'll get to what is fatal in a moment). So Bruno passes the father and son in their car as they go through the village, but those two eventually catch up with Bruno. There's a fight. There's violence. But no death. Bruno thinks he'll be able to control his daughter when he finds out she is out with a man at 1:00am, but when she appears, he's taken off guard by her age and beauty. She clearly doesn't need her father anymore, and clearly won't listen to him. When Bruno gets caught by the employer he screwed over, it's another instance of life catching up, but not being fatal.
Coincidentally, Roberto hates being chased. When he's in the restaurant where the fight breaks out, there's a woman giving him eyes. He's clearly uncomfortable with it, and makes no movement on this woman. He obviously is not comfortable not being in control. Whether he's living a boring life and not pursuing girls, at least he does so on his own terms. And that allows him to be comfortable. Of course, the question of the movie is whether or not that comfort is worth it to him, so there you go...what's a man to do?
But back to fatality. What is fatal, after all? Fatal is the girl at the train station who gets picked up by her brother. That is it. That's over. Fatal would be if Bruno's wife re-married. These would not be examples of chases that go in the same direction, these are things in life moving head-on, in the opposite direction as our protagonists.
Momentum is essential for the film, and the need for momentum is their undoing. There is the need to always accelerate, to keep going. And once you are on a ride: whether it's law school or a car ride, the further into it you go, the harder and harder it is to get off. Roberto thinks about leaving on the bus, but Bruno stops him. He tries to take a train, but again, this trip and the momentum prove too hard to escape. And he could drop out of law school, but he's only got a year left. He seems not to be in love with it, but why stop now?
The momentum is stopped by being hit head on. Ultimately, nobody chasing them can stop Bruno or Roberto. Chasing others doesn't lead them astray. They may be slowed down by the events of life that chase them, whether priests who are broken down or motorists they've wronged, but ultimately, they can keep going. Not until life hits them head on, going the other direction, does the momentum stop and ultimately lead to their death. At first it's a girl who is going in another direction. But even on the road, nobody can catch them, just face them head on. And when they face that truck head on, they must totally bail at the last moment. Hitting the brakes and the post on the side of the road.
The road trip is life. Momentum is hard to maintain, and the need to always increase speed ends up being their undoing. They both touch that lucky pepper at the end, but only Bruno has the luck needed to survive.