This slapstick road movie feels tossed off by people on a raunchy bender. I mean that as a good thing. The trouble with Hit & Run is that it can’t sustain its trippy effervescence. The business of getting the plot from A to B, or maybe even to C if we’re being generous, keeps getting in the way. Dax Shepard, so good on Parenthood as the Peter Pan-ish Crosby Braverman, is the man of the hour on this baby. He wrote the script, co-directed with David Palmer and plays the leading role of Charlie Bronson (not the tough guy actor, but the real-life British prisoner Tom Hardy played in the 2008 film). I know, I’m getting off track. Get used to it. So does the movie. Charlie, whose real name is Yul Perrkins (after Yul Brynner, the kingly star of The Magnificent Seven), has been living in a small-town California backwater, put there by the witness protection program and watched over by Randy (Tom Arnold), a bumbling U.S. marshal. Charlie is bored out of his mind, except for the sexy company of girlfriend Annie (Kristen Bell, Shepard’s real-life fiancée). Annie has a big-time job offer to teach conflict resolution at UCLA in big-time Los Angeles and Charlie/Yul is determined to drive her there. Don’t ask why. Logic is not in the credits. Just know that soon everyone is on the tail of Charlie and Annie, including Randy, her obsessive ex-boyfriend (Michael Rosenbaum), and a trio of bank robbers Charlie helped put away. The lead robber is Alex (as very funny Bradley Cooper in dreadlocks) and he thirsts for revenge. Writing this is making me sleepy, much like the movie did when the plot swerved from the zingy chemistry between Shepard and Bell. Their spark is doused by car chases that never stop. Never. Shepard worships the 1977 Burt Reynolds car movie Smokey and the Bandit. He loves cars so much that many vehicles on display here are from his private collection. I wish I shared his enthusiasm. I wish I cared. I don’t. Despite a few scrappy twists and turns, Hit & Run is ultimately a dead end.