April 12, 2002 | It's a classic example of bait and switch in reverse: The ads for Changing Lanes promise a routine blood-and-thunder vengeance flick, complete with car wrecks and other carnage, but the movie itself is something more substantial and intelligent - and much, much more morally complex.

Mind you, the advertising guys aren't entirely off the mark. Mixed signals are flashed throughout most of this uncommonly engrossing drama, as director Roger Michell (Notting Hill, Persuasion) sustains the speed of a slam-bang action-adventure, and goads us - initially - into expecting a steadily escalating tit-for-tat conflict that brings out the very worst in two increasingly acrimonious adversaries. That the movie plays the race card and the class card only serves to stoke our assumption - again, initially - that, sooner or later, somebody is going to open up an economy-size can of whup-ass on somebody else.

Time and again, however, Changing Lanes subversively upends expectations. Characters who at first appear transparent and predictable turn out to be ambiguous and multidimensional. (This applies even to the kinds of supporting characters who, in lesser movies, merely serve as utilitarian cogs in the plot mechanics.) And while the narrative hinges on one or two incidents that strain credibility, most of what happens rings emotionally, psychologically and dramatically true in ways we don't usually experience in garden-variety, button-pushing melodramas.

Credit Michell and his razor-sharp screenwriters, Michael Tolkin (The Player) and newcomer Chap Taylor, for setting the movie into high-velocity motion right out of the blocks. The early scenes briskly set the tone and provide exposition while nimbly intercutting between Gavin Banek (Ben Affleck), a Wall Street lawyer at the top of his world, and Doyle Gipson (Samuel L. Jackson), a recovering alcoholic who's very near rock bottom.

Already a rising star at the legal firm co-owned by his father-in-law (director Sydney Pollack, again moonlighting as a first-rate character actor), Banek eagerly prepares to further enhance his standing by handling a probate case involving a multi-million-dollar trust fund. Meanwhile, over in Queens, Gipson anxiously attempts to purchase a fixer-upper home, in a desperate bid to impress his estranged ex-wife (Kim Staunton) so she won't move to Oregon with their two young children.

Both men are on their way to the same courthouse when they both veer into the same lane at rush hour on FDR Drive. Their cars, and their destinies, collide.

Mindful of the ticking clock, Banek wants to settle the matter right away - right now, dammit! - and literally offers Gipson a blank check to cover any damages. But Gipson, who just happens to be an insurance salesman, wants to play by the rules, exchange information, do the right thing…

Banek can't wait, won't wait, and speeds off. Unfortunately, he leaves an important file - the very heart of his law firm's claim to control that humongous trust fund - at the accident scene. Even more unfortunately, Gipson shows up late at family court, and doesn't get the chance to talk about his home purchase before the judge OK's his wife's move to Oregon.

From these interlocking misadventures, a blood feud gradually evolves. Gipson faxes Banek. Banek phones Gipson. Gipson threatens to destroy the file. Banek pays a disreputable computer hacker (Dylan Baker) to destroy Gipson's credit rating. One thing leads to another, and nothing good comes from any of it. And then things get worse.

No doubt about it: In synopsis, Changing Lanes sounds like the scenario for a mano a mano revenge drama (or, with a little tweaking, a jet-black comedy). And yet, without ever slackening the pace of his storytelling or loosening his grip on our attention, Michell manages to make the movie richer and deeper by taking time to reveal hidden depths of his lead characters, making them at once dangerously impetuous and painfully self-aware.

Banek especially is shocked at his own capacity for full-bore nastiness, appearing as though, after each step he takes, he feels he has violated his sense of self. He begins to question not only himself but also his place of work - indeed, he questions his work, period - and rightfully suspects that there's something profoundly fishy about the probate case his father-in-law is so determined to quickly wrap up.

Gipson starts out as a flawed but sympathetic victim - a working-class African-American who's sorely mistreated by an affluent white professional - but he, too, gradually emerges as something more complicated than a quick-sketch stereotype. In a key scene, Gipson's well-intentioned AA adviser (nicely underplayed by William Hurt) suggests that Gipson is "addicted to chaos" and actually thrives on conflict. Maybe, just maybe, he's taking advantage of an increasingly bad situation to vent long bottled-up rage.

I wish Changing Lanes had ended about five minutes before it does - the final scenes are just a bit too neat for my taste - but there isn't much else I can criticize about the film. And there probably aren't enough good things I can say about the performances of the supporting players - note Toni Collette as Banek's workplace confidant and former mistress, and Amanda Peet as his shrewder-than-she-looks wife - and the two leads.

Affleck skillfully plays against his image of arrogant cockiness to reveal a smooth operator whose self-doubt leads to self-loathing as he contemplates how deeply he has sunk into a moral sewer. And Jackson is every bit as powerful as a man driven beyond his capacity to restrain his worst impulses, who becomes all the more dangerous as he discerns he has nothing left to lose. To pay their performances and the movie that showcases them the highest possible compliment: Neither character comes off as a hero or a villain. Rather, they come off as flesh-and-blood human beings.