Certain books are for a certain time. Read after the right moment in one’s life, they may not only lose their remembered magic but become parodies of themselves. Of no piece of writing is this truer, perhaps, than Jack Kerouac’s 1957 hymn to hepness, On the Road.

To 16-year-olds eager to judge whether director Walter Salles (The Motorcycle Diaries) has done justice to the Beat bible, I say, “I hope in your eyes he has.” I was 16 when I first read it, and it’s conceivable I might have been as enraptured by the movie as I was by the novel if I’d seen the former at that impressionable age. But I didn’t. And I wasn’t.

The more anyone who watches this film has lived and learned, the less they’re likely to be able to abide it. Salles’ adaptation, scripted by Jose Rivera and executive produced by Francis Ford Coppola, is a sophomoric, cliché-infested monument to nonsense.

British actor Sam Riley plays Kerouac’s alter ego, Sal Paradise, who describes himself as a “young writer trying to take off.” He tries for the most part by hanging around Allen Ginsberg’s alter ego, Carlo Marx (Tom Sturridge), and Neal Cassady’s alter-ego, Dean Moriarty (Garrett Hedlund), while scribbling in a notebook. Considering these three would become the dominant figures of the movement, it’s unbelievable how pedestrian their antics prove, not to mention how through-the-roof the picture’s corn quotient is. Could the soundtrack have more bongo music?

Coppola’s been trying to get this thing made since 1979, and has commissioned scripts from countless writers only to toss the results and start from scratch. When I had dinner with novelist Russell Banks in 2005, he mentioned he’d been hired to do an adaptation, which Sofia Coppola was set to direct. How we ended up seven years later with the Brazilian filmmaker working from a screenplay by Rivera is anybody’s guess, and no one’s good fortune.

Here’s the bugaboo — Sal shares his philosophy of life: “The only people that interest me are the mad ones,” he declares in a breathless voiceover. “The ones who are mad to live, mad to talk, desirous of everything at the same time, the ones that never yawn or say a commonplace thing but burn, burn, burn like Roman candles across the night.”

It’s like the most pretentious personal ad ever written. But the real problem, in addition to liberties taken with the original text, is that everybody in the film spends the next two hours saying and doing nothing but commonplace things — smoking, drinking, yacking and smoking some more.

Let’s be honest. When you take out all the Benzedrine-fueled baloney about the holiness of everything, how everyone’s angelic and miraculous, what you’re left with is a book about long drives. Cassady was legendary for his fearlessness behind the wheel, so much of the movie consists of Moriarty gunning an antique Hudson cross-country to one friend or another’s house. When you’re 16, Kerouac’s book may seem to concern something more cosmic, but crack those covers once you’ve got a little mileage on you, and you’ll see the harsh truth that it’s basically a diary of visits.

Sal, Carlo and Dean — accompanied by alternating squeezes Marylou (Kristen Stewart) and Camille (Kirsten Dunst) — make appearances at the pads of various friends. These bebop pop-ins aren’t notably more interesting than get-togethers between gabby acquaintances who don’t happen to be seminal Beat figures. Viggo Mortensen, for example, does a dynamite William Burroughs — but, aside from some obligatory gun play, the stopover’s about as angelic and miraculous as Sunday at Grandma’s.

Unless you’ve got a grandma who burns, burns, burns like Roman candles across the night, in which case Sunday at Grandma’s has this movie beat to hell. The novel is semidelusional drivel, and, unfortunately, Salles’ screen treatment serves only to underscore that fact. Take my advice: If you hope to hold on to a shred of your youthful fondness for the book, stay as far as possible from his film.