Jack Kerouac’s stream of consciousness novel “On the Road” comes to the screen more or less intact as a not altogether satisfying road trip into the Beat Era. The “Motorcycle Diaries” team of director Walter Salles and screenwriter Jose Rivera have made an “unfilmmable” book cinematically coherent, capturing the geographical possibilities, the feel and flavor of this blend of biography and Beatnik history.

Sam Riley (“Control”) is Sal Paradise, the “witness,” the teller-of-the-tale – Kerouac by another name.  Sal’s the restless writer struggling to write a book that will make him famous. And with Dean Moriarty (Garrett Heldund of “TRON: Legacy”), Sal’s found his muse. Dean’s “every muscle lives to twitch and go.” Dean was in Denver. Now he’s in New York. He has to go back to Denver. Then San Francisco. Then Algiers, Louisiana.

Dean, whose catch phrase is “Yes, yes yessss,” has to experience it all – high on Benzedrine, racing his Hudson down the two-lane blacktops through rain, sleet and snow – procuring and seducing women, not just his 16 year-old wife (Kristen Stewart, young and kittenish), the woman he wants to leave her for (Kirsten Dunst), and other random pick-ups – devouring books and grooving to jazz.

Dean is magnetic, with an ostentatious literacy about him. He shoplifts and swipes gas to finance his cross-country treks, seduces both women and men and bear hugs one and all. The others follow him to where the action is.

Dean is “a taker,” says Sal’s writer-pal Old Bull Lee, based on William S. Burroughs. Old Bull (Viggo Mortensen) might be a junky, raising a child with his junky wife (Amy Adams, alarmingly “out there”). But he sees Dean for what he is — Falstaff to Sal’s Prince Hal, somebody the writer understands but refuses to judge – for now.

Carlo, based on “Howl” author Allen Ginsberg, is also under Dean’s spell. Carlo (Tom Sturridge) is in love with the guy, and with the idea of composing that one, world-shaking poem.

“My mind is a veritable echo chamber of the ‘50s,” he declares. Odd, since “On the Road” takes place mainly in the late 1940s.

Screenwriter Rivera blends the novel with the biographies of those involved, and Salles further blurs that line by needlessly replacing the fictional place names Kerouac shoved into the book with their real locations. Do we really need to know that they stole gas in South Hill, Virginia, or Flomaton, Alabama?

Riley has a nice take on quizzical. And Hedlund is properly charismatic if subdued. The Dean of the book is a whirling dervish who sucks people into his orbit with his energy. The women in the tale are second class citizens, which makes the casting of three big names in those main roles a puzzle. And the film hinges far more on the sexual that the surreal, perhaps a necessary compromise.

But what Salles gets just right is the sense of speed – of lives lived too fast, of the blacktop passing before their windshield in a blur. Sal’s quest, to soak up experience, is intoxicating.

Here’s a writer who went out and met the world, drank it in and then recounted it in the same boundary-pushing whirlwind that was his experience of it.

MPAA Rating: R for strong sexual content, drug use and language

Cast: Garrett Hedlund, Sam Riley, Kristen Stewart, Kirsten Dunst, Viggo Mortensen, Amy Adams, Elizabeth Moss

Credits: Directed by Walter Salles, screenplay by Jose Rivera, based on the Jack Kerouac novel.  An IFC release.

Running time: 1:58