Is Dean Moriarty an overgrown boy still looking for his father? An intoxicant-starved addict? Rough trade who will do anything for a buck? A charismatic sociopath? A repressed homosexual unable to accept that his only real feelings are for men?

Or an incomplete soul, who finds the emptiness inside himself mirrored by the open vistas of the American West and the soullessness of dingy, post-World War II cities?

Or just an asshole?

Under the restrained direction of Walter Salles (The Motorcycle Diaries), actor Garrett Hedlund suggest all of those Deans in the provocative new adaptation of Jack Kerouac’s On the Road, which screened Monday night at the Savannah Film Festival.

Looking like a cross between Leonardo DiCaprio and a Blue Velvet vintage Kyle McLachlan, Sam Riley brings innocence, youthful energy, and an existential weariness to his portrayal of Sal Paradise, the aspiring writer who finds the perfect subject in Dean and in their travels on the road.

Of course, Sal is genuinely absorbed by Dean — he’s hypnotized at times by Dean’s power to seduce. But when crises happen, the boys — they’re hardly men — tend to flee, to avoid, to abandon. At the end of the day, Sal can’t go to the dark and wild places that Dean goes; Sal wants to get his feet wet, to feel the heat, but he’s unwilling to give himself completely to experience.

Sam Riley as Sal Paradise from the trailer

If anything, Riley’s Sal seems a little too stable, not quite edgy enough for a friendship with Old Bull Lee, the character modeled on William Burroughs (a sharp Viggo Mortensen). The scenes with Dean, Sal, and their entourage at Old Bull Lee’s place in Algiers, Louisiana have a particularly pleasing decadence.

Tom Sturridge’s Carlo Marx (the fictionalized Allen Ginsberg) is smooth-skinned, darkly idealistic, and passionately in love with Dean. He needs Dean for inspiration, but less than Sal does.

Dean’s female love interests Marylou (Kristin Stewart) and Camille (Kirsten Dunst) are obviously critical to the action, but On the Road is ultimately a boy’s story. Sal has a brief, passionate affair in a migrant labor camp with Terry (Alice Braga), but the woman seems less important than the experience to the fledgling writer.

Steve Buscemi, looking a heck of a lot like John Waters, has a few great moments after he knocks on the motel room door of the two handsome young men — Dean and Sal — to whom he has given a ride.

Kerouac, director Salles, and screenwriter Jose Rivera keep the disjointed story moving — some scenes tie directly to others, but many are isolated.

I didn’t know if it was possible to capture the essence of On the Road on film, and I’m not sure about that even now. No film can capture the richness of Kerouac’s language, and the defining forms of actors’ faces and bodies limit our imaginations.

But the limitations here feel about right — maybe as close as filmmakers could come to channeling Kerouac’s novel.

Here’s the trailer: