“Hit & Run,” which opens across South Florida and the nation today, is about fast cars, so let’s just cut to the chase. Sometimes, a movie arrives that is so vile – so utterly reprehensible in every conceivable way – that its existence is a shame on the very nation that produced it and a ghastly stain on the resumes of every single person involved. “Hit & Run” is one such film.

A passion project of sorts for writer/director/actor Dax Shepard, “Hit & Run” is a soul-crushing, mind-poisoning 100-minute celebration of car porn and machismo. Shepard plays Charlie Bronson, a former getaway driver in the U.S. Witness Protection program, who agrees to drive his girlfriend from Milton, Calif. to Los Angeles for a teaching job, only to be pursued by various and sundry characters, including a buffoonish U.S. Marshall (Tom Arnold) and his former partner (Bradley Cooper) on whom he ratted to the police. Kristen Bell is saddled with the thankless role as his girlfriend, a pretty, obedient young thing inexplicably attracted to the charmless Charlie, with whom she shares the chemistry of oil and water.

Over the course of the journey, all matter of vintage, modern and barely drivable automobiles are pilfered, destroyed and requisitioned, to the soundtrack of bloated classic rock and the mindless prattle of Shepard’s dialogue, another reminder that not everybody can be Quentin Tarantino.

Shepard’s fascist, skuzzy humor invariably comes at the expense of every minority group he can conjure: “Hit & Run” is antigay, racist, ageist and sexist – no “ist” has been unexplored. The female characters are idealized ornaments with all the independence of dogs on leashes. The movie’s one African-American character is a wifebeater-donning pit bull owner who becomes the butt of the film’s most disgusting joke. A cruel visual of flabby, nudist senior citizens in a motel room is employed an excruciating two times, and there’s an extended set piece involved that hilarious old comic chestnut, prison rape. It’s clear that Dax Shepard hates just about everyone other than himself.

It’s also worth noting that Shepard, who codirected with David Palmer, has no vision as a filmmaker or visual stylist. The digital cinematography in “Hit & Run” has the look of cheap plastic – it’s one of the most unfilmlike films I’ve seen in a movie theater – and his shaky-cam action scenes flounder unsuccessfully for coherence. Any sense of depth or dimension in the framing is beyond his abilities.

It makes sense that Kristen Bell would partake in this quagmire, given that she’s married to Shepard in real life, and I can understand Tom Arnold’s participation, too: It’s not like producers are lining up around the block to cast him in projects. But the really talented people who show up in major roles and cameos – Bradley Cooper, Jason Bateman, Beau Bridges, David Koechner, Sean Hayes – should be ashamed of themselves for taking a paycheck to promote unfunny, incompetent hate.

For one interminable stretch of “Hit & Run,” the dialogue is usurped by images of fetishized cars careening along a sun-baked parking lot, through a building and back into the open air. The movie, finally, has been reduced to a sports car commercial, lacking only the dramatic voice-over narration about horsepower statistics and all-wheel drive. In this, Shepard has perhaps found his meager calling as a director.