We critics often get asked how we can sit through so many bad movies. The answer — apart from the fact that it isn’t exactly hard labor — is that even a lot of middling Hollywood product has moments of baseline entertainment value. The average Adam Sandler comedy is funnier than the worst Adam Sandler comedy; most mediocre superhero movies are better than “Suicide Squad.” And when it comes to the brain-dead action comedy that “ironically” reboots a piece-of-crap television series from the ’70s or ’80s, “Starsky & Hutch” and “The Dukes of Hazzard” were flat-out masterpieces compared to “CHIPS,” an ultra-violent and ultra flavorless buddy movie that’s so dedicated to hitting the generic sweet spot of “what the audience wants” that it actually had to go and capitalize the “i” in the title, as if that quirky lower-case digit from the TV show was just too threateningly odd.

“CHIPS” was written and directed by its co-star, Dax Shepard, an actor with a puckish off-center charisma I’ve always enjoyed. But the movie is what it looks like when mindless slumming convinces itself that it’s hip. Shepard has a distinctive fugly appeal — he’s tall and loose-limbed, with the preening confidence of a star, and with eccentric features that are just this side of handsome. He looks like Martin Short with Peter Weller’s bird-like stare grafted on; he’s like a sexy alien. In “CHIPS,” he plays Jon Baker, a former competitive motorcycle rider whose beaten-up body is a scarred welter of aches and pains (he pops opiates like candy), but he’s inept at everything except riding that chopper.

Baker, after years of training, has worked his way up into the storied ranks of the California Highway Patrolmen, on their wide-bodied Ducati bikes. Shepard did much of his own stunt work, and he’s clearly having a good time showing off his motorcycle acumen: the popped wheelies and high-velocity fearlessness (accentuated by shots mounted on the handlebars), the ability to snake a bike down a serpentine L.A. staircase. As a TV show, “CHiPs” had some fairly elaborate action set pieces for its time, but in “CHIPS” all the speed and mayhem is a numbing semi-joke: Evel Knievel meets “Bad Boys IV.”

Baker gets teamed with a new officer who, unbeknownst to him, is an FBI agent. Frank Poncherello (Michael Peña) — that’s his alias — has been assigned to the CHP to flush out a coterie of dirty cops who’ve stolen $14 million. There’s never any big mystery about who they are or what they’re up to (their ringleader is portrayed by a bearded and snarling Vincent D’Onofrio, who should really take a break from playing heavies), yet “CHIPS,” despite its moments of frat-house goofiness, plays the cop caper in a glumly straight fashion. The film’s model is — or should have been — the movie version of “21 Jump Street” and its sequel, but the co-directors of those bumptious nihilistic undercover burlesques, Phil Lord and Christopher Miller, knew how to turn comedy into suspense and thrills into media-mad absurdity. Shepard just sprinkles overstated banter onto a generic plot and bits of pedal-to-the-metal action, as if he was serving the action-comedy gods by sticking the usual ingredients in a blender and pushing “purée.”

It’s doubtful there’ll be much of an audience to drink it up. The movie’s fudged-out lack of funniness starts with Shepard, who plays Baker with a stoned version of his usual fast-break timing. Baker, in addition to being a drug addict, is a whipped husband married to a princess who keeps him in the doghouse (she’s played by Kristen Bell, Shepard’s real-life spouse), and after too much couples’ counseling, he’s become an L.A. therapy-head who jabbers on about things like “closure” and “deflecting.” But he’s also a junk-food junkie and testy violent daredevil. He’s whatever Dax Shepard feels like playing at any given moment, so the character never quite gels.

Peña’s “Ponch” is a more amusing presence, a level-headed macho hard case who can’t believe he has to put up with such a flaky partner. Peña knows how to understate, even when Ponch can barely contain his libido around a woman in yoga pants. There is also, of course, much winky homoerotic slapstick panic between the two men, including a face-meets-nutsack moment that looks like it was a lot funnier for the actors than it turns out to be for us.

It’s become routine for a movie to put ’70s trash in quotation marks, but “CHIPS” actually encourages you to think it’s being ironic about its own badness. “Look,” the film seems to be saying, “it’s the same old junk! But we know how junky it is! Isn’t that a laff riot?” There’s one scene of unforced hilarity, when Ponch informs Baker about the new mainstreaming of a certain sexual practice (the joke is in Peña’s casually serene polymorphous perversity). The movie also has some grisly violence (too much of it), including a decapitation and a moment where a major character gets three of his fingers shot off. “CHIPS”never does more than nod in the abstract to the original Larry Wilcox/Erik Estrada TV series, with its stoic hunk heroes in their skintight police-geek uniforms, yet this is one (rare) case where I wished a movie based on something that was hardly worth adapting had stuck closer to the original show. There’s a running gag about how those khaki uniforms now look like they belong on UPS deliverymen, and that kind of sums up “CHIPS”: It takes cops who once had an aura and turns them into Paul Blart with attitude.