The advantage of buying bullets by the color of their box and the disadvantage of having a religious relic on the car dashboard are two kinky little plot points which mushroom into high drama in Crash, and the beauty of the results is that you never see them coming.

Paul Haggis, in a flashy, razzle-dazzle debut as film director, surprises as much as he stuns, unraveling this credibly complex portrait of racial conflicts boiling and bubbling in L.A. of today. He came up the storyline himself, crisscrossing an intricate variety of interlocking plots while still stirring the cauldron of distrust and unrest in this melting pot. The script-by Haggis and producer Bobby Moresco, both men still wearing their Million Dollar Baby Oscar glow-musters some unexpected laughs as well.

Other than the fact that it is also the work of an original Canadian thinker, this Crash is no kin to David Cronenberg's same-named 1996 opus in which automobile wrecks were foreplay for James Spader and Holly Hunter, but it does begin and end with one car rear-ending another and, midway through, has a colossal collision-and-rescue sequence.

The complicated plot is neatly set off in stars. A number of name-brand actors, used sparingly and smartly, play well with the other children-plus, they bring easy charisma to quick cameos and add up to a superb ensemble. Most of the players are rewarded with dimensional roles to play. No pun intended, but none of the characters is depicted as all-black or all-white, but rather in gradations of gray. For a violent film, it is inordinately humane and refreshingly unpredictable. Innocence is repeatedly, in one brutal segment after another, placed in harm's way, and Haggis lets you sweat out the uncertain results.

Matt Dillon, on looks alone, brings an instant believability to the role of a racist cop who degrades an upscale black couple (Terrence Howard and Thandie Newton) and, by bizarre accident, stumbles into a heroic act of redemption. A more tragic fate awaits his partner (Ryan Phillippe)-ironically, because he makes a stand against Dillon's blatant bigotry.

Sandra Bullock, a long way from cuddly and Miss Congeniality consideration, is stridently satisfying here as the pampered, epithet-flinging WASP wife of the local DA (Brendan Fraser), who, embarrassingly, has been victimized by carjackers (Larenz Tate and rapper Chris "Ludacris" Bridges). An easily riled Iranian shopkeeper (Shaun Toub) butts heads with a Hispanic locksmith (Michael Pena), basically over miscommunication.

Two sharp cameos of civic cynicism come from William Fichtner as a manipulative sleazeball and Keith David as a pragmatic, if a tad tarnished, LAPD big-brass. Jennifer Esposito and the always excellent Don Cheadle weave through the assorted plot turns as an amorously involved cop couple not without their Hispanic/African-American battles.

These storylines intersect with frequent violence and friction, crocheted so densely into place by the screenwriters that they practically seem plausible, if not inevitable.