Rupert Grint goes from sidekick to spotlight in Driving Lessons, a slight coming-of-age comedy that probably won’t make viewers forget about Ron Weasley anytime soon.

Grint matures agreeably as a contemporary real-world teenager in this attempt to break free from his Harry Potter alter ego, although it’s the latter that will likely draw curious audiences to the theater. It doesn’t help his cause that his new character, Ben, shares some of Ron’s neurotic shyness.

Still, give Grint credit for the finest performance among an ensemble that includes Oscar nominees Julie Walters (Billy Elliot) and Laura Linney (Kin­sey) as middle-aged women vying for control of his life. No wonder the kid is so depressed and antisocial.

As the film opens, Ben is struggling to earn his driver’s license while rehearsing his part in the church play with his pious, overbearing mother (Linney). He takes a part-time job caring for a washed-up actress named Evie (Walters) whose vulgar, carefree nature encourages Ben to loosen up, enjoy life and defy authority. Evie becomes more dependent on Ben as her platonic companion, leading to a wild adventure during which their loyalty teaches lessons that span generations.

The script by director Jeremy Brock is reminiscent of less edgy version of Harold and Maude. In terms of tone, it falls more in line with the recent string of quirky working-class British comedies. It’s mischievously charming enough for the first half, until Brock turns it into a road-trip movie with some benign plot twists that lead to a predictably heartwarming outcome.

With the lack of character or story development, audience mem­bers are left to try to identify with Ben, because they certainly won’t with either Evie, whose over-the-top eccentricities quickly turn obnoxious, or Ben’s mother, who becomes little more than a one-dimensional villain.

Driving Lessons seems too committed to combining familiar formulas to carve out its own niche, and as a result it never really gets into gear.

Driving Lessons

**

Rated PG-13, 98 minutes.
Opens today.