Everything wrong with “Hit and Run” can be summed up in a moment when Dax Shepard’s character tells his girlfriend Annie (Kristen Bell) why he chose the name Charles Bronson for his alias in the witness protection program.

Charles’ father named him Yul, after Yul Brynner. Charles complains that no one in his generation knows who Yul Brynner is, so when the opportunity arose, Charles chose the alias Charles Bronson, after a British criminal of the same name.

The kicker: Charles Bronson is also the name of an actor who starred with Brynner in “The Magnificent Seven.” The bit is supposed to be funny, but it’s really a sad reflection on the fact that yesteryear’s great actors are forgotten, and we’re stuck watching “Hit and Run.”

As the film’s writer and co-director (with David Palmer), Shepard to his credit comes up with a few decent scenes and a pretty good plot. Charles is a former getaway driver in witness protection for ratting out his old crew. His girlfriend, Annie, is an academic type specializing in nonviolent conflict resolution. When a teaching position focusing on her specialty opens up in Los Angeles, Charles decides to blow off his witness protection officer, the bumbling, ridiculous Randy (Tom Arnold), and drive her to LA to apply. But Charles’ former partner, (Bradley Cooper), has recently been released from prison on parole, and when he finds out that Charles is coming home, he sets out to exact revenge.

Shepard’s TV show “Parenthood” is the less funny version of “Modern Family” – it had essentially become an evening soap opera when I stopped watching it midway through season one. Dax himself is fairly good in “Parenthood,” and not even terrible here, with his off-the-cuff humor, but it can’t save his film from crashing and burning.

For her part, Bell (“Couples Retreat,” “When in Rome”) is mostly just annoyingly cliché. For being into nonviolent conflict resolution, she resolves almost none of the conflict in this film non-violently. Indeed, her whole career seems to be based on the academic study of something the film seems to portray as nonexistent.

Cooper is the best of the cast, as would be expected – he’s a jock with dreads, whose funniest dialogue unfortunately also centers on being raped.

And that’s where the film drives off the cliff and leaves decent comedy far behind. Annie is generally unaffected when she listens to Debbie (Kristin Chenoweth’s sassy throw-away cameo character) talk about getting date-raped and having abortions (we are supposed to laugh at the line), but becomes offended the second that Charles uses the word “f-g.” She’s fine with the F-word, which riddles the film, but f-g crosses into hate speech (for the record, I think it’s best to avoid both terms).

Somehow her insinuation that all rednecks are “rapists” doesn’t, though. Perhaps the worst part, Charles crosses nearly every racial barrier on the planet in a discussion of skin color and sexuality, saying that he thinks black men see white men as essentially “butch women,” and says that white guys think of Asians in the same way. He then unleashes on Hispanics to effectively offend nearly everyone. This is supposed to make Cooper’s character feel OK about being raped in prison or something. It’s mostly just disturbing.

Then there are the visually repulsive scenes when different characters stumble into the wrong hotel room only to find four old, naked swingers with assets exposed for maximum gross-out effect. The film’s squealing tires and burning rubber don’t compensate for the garbage it presents as entertainment.

But of course, what should we expect from a film about characters that don’t remember the era in Hollywood when Brynner ruled the box office? Somehow the jokes about abortion and rape, while offensive, are actually a rather sad reflection on what Shepard and crew think is entertaining. For all his talent at writing and even some at directing, he steers the film into pretty disgusting terrain and “Hit and Run” takes a wrong turn only a few minutes out of the garage – from which it never corrects course.

Better to simply steering clear of this waste of time.