"Mad Max," now laying rubber across several area screens, is far and away the most profitable Australian movie ever produced. Already a box-office sensation in Australia, Japan, West Germany and Spain, this $358,000 exploitation melodrama -- a hard-riding vigilante car opera in which steely-eyed highway patrol cops relentlessly pursue degenerate motorcycle desperados across the long, undulating highways of Queenland sometime in a marginally more barbaric future -- is expected to return $20 million in rentals from markets outside North America.

Needless to say, "Mad Max" can anticipate an enthusiastic reception here, where the kinetic thrills and sublimated aggressions director George Miller manipulates with ruthless effectiveness are not exactly unknown. As a matter of fact, "Mad Max," which combines the high-speed pictorial dynamics of Steven Spielberg's "Duel" with usefully primitive plot elements from "Death Wish" and "Walking Tall," seems to be a foreign film returning to the source of its inspiration.

Evidently fearing that a mass American public would regard Australian English as a foreign language, the importer has dubbed the dialogue with the usual assortment of inexpressive, disembodied voices inflicted on real foreign language productions. Of course, it's impossible to get the driver's seat over on the left side by means of dubbing, but it's probably hoped that the customers who notice will assume the image was accidentally reversed.

The title refers to Max Rokatanski (Mel Gibson), the ace of the Main Force Patrol, the law enforcement branch charged with policing the highways in a civilization where legal processes apear to have broken down. At any rate, Miller displays a conspicuously broken-down edifice called the Halls of Justice, where even the lettering is askew and only the stalwart MFP seems to be functioning.

The pilot, more of an expedient sham than an organic necessity, is contrived to rationalize getting Max mad enough to clear the roads once and for all of outlaw vermin, The Nightriders, commanded by a brute known as Toecutter (Hugh Keays-Byrne), whose shaggy, two-tone mop is gathered into a samurai topknot.

The gang itself recalls the scroungiest bandit elements from not only samurai melodramas but also American Westerns, Italian Westerns and motorcycle sagas like "The Savage Seven," which were, of course, modern-drag Westerns. Miller even throws in a trace of homosexual flirtiness in the deviate tradition that runs from Howard Hughes' "The Outlaw" through Andy Warhol's "Lonesome Cowboys."

However, the Nightriders are such self-evident scum that it seems a little quaint to worry about whether Max and his colleagues have sufficient dramatic cause to run them off the road. Miller isn't very slick at this expository busywork. I thought the wanton murder of Max's sidekick, an ebullient motorcycle cop called Jim Goose (Stan Brisley), was enough motivation for this sort of visceral cinematic fairy tale, but Miller goes on to add Max's wife (Joanne Samuel, a lively presence with a dazzling dimple smile) and toddler to the victim list, which amounts to overdoing it in the most underhanded way.

The enmity seems wittier and more persuasive, too, when it's just a given -- evidence of a breakdown of law and order sometime in the past that has led to an anarchic situation. Although Miller begins the movie with a long shot down a highway called Anarchie Road, he fails to sustain the suggestion of futuristic terror, recalling aspects of "A Clockwork Orange" and "Deathrace 2000."

Hackneyed at exposition, Miller demonstrates breakneck prowess at chase sequences and terrifying shock effects. The opening sequence, in which the MFP is depicted in hot pursuit of a crazed motorist who exclaims, "I'm a fuel-injected suicide machine!" reveals a filmmaker in impressive control of the mechanics of exciting the senses through fast-moving and astutely juxtaposed images.

Miller's ace-in-the-hole appears to be accelerated sense of timing that allows him to deliver the payoffs -- spinouts, collisions -- slightly before one anticipates them. Once subjected to this propulsive, stunning method it's a little difficult to revert to banal, obligatory exposition.

In "The Warriors," Walter Hill contrived to sustain a virtually nonstop fantasy of urban violence. Miller's impulses seem to be leading him in the same direction, but for the moment he still finds it necessary to pull in for superfluous melodramatic pit stops. With the success of "Mad Max" under his belt, he may now be tempted to go all out, a prospect at once fascinating and frightening.