Back in 1985, Brett Easton Ellis opened “Less Than Zero,” his novel about young Southern Californians unable to connect, with the less-than-subtle double entendre: “People are afraid to merge on freeways in Los Angeles.” Twenty years later, Paul Haggis’s film “Crash” extends the simile: Unable to merge, Angelenos instead smash headlong into one another. “In L.A. nobody touches you,” a groggy accident victim ruminates in the movie’s first scene. “We’re always behind this metal and glass. … I think we miss that touch so much that we crash into each other just so we can feel something.”

Happily, while the automotive metaphor may be tired, the movie that unfolds from it is anything but. “Crash” is an extraordinary film, a complex and cutting exploration of racial grievance and mistrust played out as a series of collisions between characters propelled by prejudice. A black studio executive and his wife are pulled over and humiliated by a white cop; the white district attorney and his wife are carjacked by a pair of black thieves; an Iranian shopkeeper whose store has been vandalized seeks retribution against the locksmith he blames for the crime; and on and on in a cycle of interlocking stories that ultimately encompasses characters white, black, Hispanic, Asian, Middle Eastern, and even Russian.

Writer-director Haggis, a long-time veteran of television, is best known for having penned the script to last year’s Oscar-winning “Million Dollar Baby.” But where that film featured a fairly conventional story line interrupted by a single, paralyzing punch, “Crash” pummels unrelentingly. Into its deceptively short running time (a mere 100 minutes) the film squeezes in a hit-and-run, two fatal shootings, two carjackings, several accidents, and a litany of racial confrontations that culminate in three harrowing climaxes. Few of these encounters, moreover, play out as feel-good Hollywood sermons about the wrongness of bigotry. Mr. Haggis is brave enough to show that even bigots can have their reasons, and they are not always irrational ones.

Yet remarkably, “Crash” is not a bleak film. No sooner has Mr. Haggis constructed his world of unbridgeable racial divisions, of malice and misunderstanding, than he begins to dismantle it, infusing the movie with a redemptive, humanist spirit. Acts of mercy and compassion take place in unexpected quarters. One heroic rescue is followed by another that seems at first to be a case of divine intervention, though in a clever twist, it is later shown to be the product of more worldly mechanisms. Mr. Haggis also leavens the movie’s serious content with frequent dashes of comedy – a sly subversion in which two young black men who complain of being mistaken for criminals turn out to be criminals, a hilarious monologue about the forensic obsessions of the Discovery Channel.

The script is a marvel: Concise in the manner of the very best television writing, and structured with a classical precision in which each theme is repeated, fugue-like, in alternating keys. Two wives – one white, one black – rebuke their husbands for not protecting them from a racial affront. A white cop is asked by his black superior not to report a white racist in the department; a black cop is asked by his white superior not to report a black drug-user. Two policemen are initially introduced as brave and cowardly, respectively, only to have these roles reversed by film’s end.

Such formal composition could easily come off as dry and schematic, but Mr. Haggis keeps “Crash” moving with such pace and intensity that this is never a danger. There are a few directorial excesses – a dirge-like score that occasionally descends into bathos, and an overly manipulative scene in which a child’s life is threatened – but his hand is remarkably sure for a rookie film director, especially given the narrative and thematic complexity of the work.

Thanks to its raw emotion and sharp-edged interactions, “Crash” is an actors’ film, but unlike many – e.g., “21 Grams” – it does not revolve around a few big Oscar-bait performances. Rather it is composed of a series of miniatures, characters sketched with surprising detail in a few short scenes each. The deep cast includes Don Cheadle, Thandie Newton, Terrence Howard, Brendan Fraser, Ryan Phillippe, Larenz Tate, and Tony Danza, among others. Of particular note are perennially underrated Matt Dillon as a racist cop who is more (or perhaps less) than he appears; the rapper Ludacris, terrifically witty as a racial conspiracy theorist who is also a crook; Michael Pena, indelibly touching as an honest locksmith and protective father, and Sandra Bullock, who as a chilly trophy wife gives perhaps the least perky performance of her career.

It’s tempting to call “Crash” the best film of the year so far. But that would be to damn it with faint praise, given the extent to which filmmakers cater to the academy’s attention deficit disorder by withholding their top efforts until December. The truer test will be how the movie stacks up eight months from now. I wouldn’t bet against it.