A couple of years ago, Magic Trip, the artful reassemblage of the 16mm footage shot on Ken Kesey's 1964 "Merry Pranksters" bus trip, gave us rare moving footage of Neal Cassady. And, watching this well-meaning but laboured and disjointed adaptation of the 1951 Jack Kerouac novel that came to be seen as defining the Beat Generation, I couldn't get those images of him out of my head.
At the wheel of the Pranksters' bus, Cassady was a frenzy of drug-fuelled energy. Equal parts Fritz the Cat and Aladdin's genie, he was wired enough to power a small city and you had to marvel at the fact that they made it to the Nevada border, never mind New York.
It's hard to find that man in Hedlund's incarnation of him (or rather his fictional analogue, Dean Moriarty; Kerouac's publisher insisted all his characters have new names). He's certainly a laid-back sybarite whose appetites for both drugs and sex are so voracious and catholic they seem almost post-modern in this anxious age: watching him smash Benzedrine Nasal inhalers to make instant-hit tea out of the contents will leave the unhorrified in awe of his inventiveness.
But he's altogether too smooth and self-regarding to be the Moriarty Kerouac gave us, more bedraggled peacock than scrappy seagull.
A film adaptation of On The Road has been a long time coming. Kerouac himself tried and failed to get Brando interested in the 1950s and Francis Coppola has tried several times to get projects to fly since he acquired the rights in 1979. (Mercifully the one that had Brad Pitt as Moriarty never got off the ground.)
On the face of it, Salles, who made the overrated Che Guevara road movie The Motorcycle Diaries, might have seemed a good, non-commercial choice, but he approaches it with too much reverence. Both he and his screenwriter, playwright Jose Rivera, lack the courage to seize the rambling story by the scruff of the neck. The long running time is the most obvious evidence of this failure of nerve, but it is frustrating as a film because it sacrifices narrative coherence for a kind of episodic fidelity.
At times, the result is highly evocative set pieces - that Benzedrine party, a New Year's Eve, a bucolic sequence in the cottonfields when Kerouac/Sal meets the Mexican woman, Terry. But often, it seems like it's ticking the boxes: watch Dean get pulled over for speeding; see Sal get a book of poems from Carlo (a disguised Allen Ginsberg); let's have unusual sex.
Through all this, the performances struggle to breathe. Sturridge's Carlo, and Dunst as a wonderfully vulnerable Camille (Carolyn) are the only characters from whom we get a breath of real life.
The film certainly looks handsome. Eric Gautier's vistas, panoramic widescreen or tightly framed in a rain-spattered windscreen, are a treat and the sound design is brilliant too. But it's hard to shake the idea that we're watching a film about someone writing a book called On The Road, an artefact rather than a work of art.
Cast: Sam Riley, Garrett Hedlund, Kristen Stewart, Kirsten Dunst, Viggo Mortensen, Amy Adams, Tom Sturridge
Director: Walter Salles
Running time: 139 mins
Rating: R18 (drug use, sex scenes, offensive language)
Verdict: Too faithful and too unadventurous