Ben Affleck plays Gavin Banek, a young attorney whose firm is being sued for allegedly forcing a mentally-declining philanthropist to cede control of his charity to them shortly before his death. Gavin has a legal document giving his firm control that has been signed and notarized. He is due to present it in court one morning. Samuel L. Jackson is Doyle Gipson, a recovering alcoholic who is also due in court. Doyle is attempting to get his act together so that he can have visitation rights with his two young sons. His estranged wife Valerie (Kim Staunton) has plans to take the kids and move to Portland; Doyle intends to inform the court that he's purchased a home for his family so that they can stay in New York.

A fender bender leads to a day of misery for Ben Affleck and Samuel L. Jackson in Changing Lanes

As both men race to the courthouse, they have a fender bender. It happens so fast, you can't even tell whose fault it was. Doyle wants to exchange insurance information, but the arrogant Gavin simply slips him a blank check for damages and says "better luck next time." Consequently, Doyle is late for his appearance and loses his case. He storms out in a rage, only to notice that he still has one of Gavin's files. Gavin, meanwhile, finds himself before the judge, unable to produce the document he needs to prove his firm didn't commit fraud. The men encounter each other again on the street. Gavin apologizes halfheartedly and explains how desperately he needs that file (the judge has given him until the end of the day to produce it). Doyle, realizing that he can get even with the smug lawyer, refuses to give it back. Things get worse. Gavin decides that he has to get the file back by any means necessary, so he visits a "fixer" (Dylan Baker) who screws up Doyle's home loan. This, in turn, leads Doyle to strike back. And so it goes over the course of an entire day.

What I loved about Changing Lanes was the moral complexity of the story. There's no good guy, no bad guy. The film is absolutely fair in the way it shows both mens' decency as well as their rage. A lot of thrillers would have made one of the two guys a psychotic. Not this one. It rings true by showing both sides of the equation. What makes it scary is that it feels like this could really happen. We know people like Gavin and Doyle. They are perhaps neighbors, or co-workers, or friends. Maybe they are us. And under the right circumstances they do the wrong thing.

It's interesting to see how these characters react not only to each other but to themselves. Quite often, they start out feeling righteous anger, but when they stop and think about what they've done, they are horrified by the cruelty of which they are capable. There's a great shot of Doyle looking out the back window of a cab. He thinks he just stuck it to Gavin and he feels great about it. Then he sees that his actions have had a disastrous effect (and could have potentially even killed somebody) and his facial expression melts from pride to shock. It's a moment that sent a chill down my spine, due to award-caliber acting from Samuel L. Jackson. The fact that the movie can explore both the exhilaration and the shame of revenge gives it a poignancy that hits you hard.

Another strong point is the way the screenplay by Chap Taylor and Michael Tolkin adds layers to both characters' dilemmas. Gavin isn't just annoyed, he's facing jail time if he can't produce that document. The stakes for Doyle are just as obvious; he may never see his children again. The supporting characters in Changing Lanes serve to tighten the screws. Sydney Pollack plays Gavin's boss, who finds a solution to the problem that is ethically wrong; he nonetheless demands the young lawyer follow it. Amanda Peet also has a small but powerful role as Gavin's wife. She shows up to offer her husband some surprising advice that only makes his predicament worse. Doyle, meanwhile, gets nailed by his wife, who suggests that he's addicted to chaos, not booze. Toni Collette and William Hurt also have supporting roles as Gavin's partner/mistress and Doyle's AA sponsor, respectively. Their characters have their own ways of cranking up the moral drama.

The level of writing in this picture is just phenomenal. All these different outside elements implode on the central figures simply because they are flawed men who continually create bad situations for themselves. When fate brings them together via an automobile collision, it's like the irresistible force meeting the immovable object. Each man is too full of righteousness to simply let it go. They dig their own graves. We live in a time when people feel an obligation to vindicate themselves over anything and everything. A minor fender bender can become a reason to ruin the life of the son-of-a-bitch who hit you. The movie understands - and depicts - the self-destruction inherent in trying to make somebody else pay.

Affleck and Jackson are perfect in their roles, making you feel every bead of sweat that drips down their nervous foreheads. Gavin Banek is a nice rebound for Affleck, who has too often coasted in subpar action movies. It's great to see him show his potential again. Jackson is also very good. In fact, he's brilliant. It's heartbreaking to watch Doyle because you know he's brought all this misery on himself. By trying to get even with Gavin, he threatens to ruin everything he's worked so hard to achieve and yet he can't stop himself.

There's real tension in this movie and director Roger Michell (Notting Hill) squeezes out every last drop of it. To some, the ending may seem a little too pat as it manages to find a happy resolution for both men. I didn't mind it because I know what Changing Lanes is trying to say: if we all spent as much energy being nice to each other as we do trying to screw one another, there's no end to the wonderful things we might achieve.

( out of four)

Changing Lanes is rated R for language. The running time is 1 hours and 40 minutes.