As one scene ended and another began during "Hit & Run," a common thought kept reoccurring in my mind: Was that supposed to be a funny scene? This is not a good question to have, especially if the movie in question is supposed to be a comedy.

Unfortunately, "Hit & Run" is technically marketed to audiences as a comedy, though there are enough car chases to make a viewer wonder if they accidentally walked into the ugly stepbrother of "Fast Five" and "Drive." It also has a romantic storyline with hints of a quirky indie movie and the profane faux intellectual dialogue of a Tarantino film. "Hit & Run" attempts to be all these things, handling each one with the grace of a demolition derby.

The movie follows Charlie and Annie, played by real-life couple Dax Shepard and Kristen Bell. Charlie is in the Witness Protection Program, under the protection of an aggressively unfunny Tom Arnold, for witnessing a bank robbery and testifying in court. When Annie gets a rare teaching opportunity in Los Angeles, however, Charlie figures it's a good enough time and reason to move out of their unassuming small town and re-enter society.

Sadly for the cute couple, Charlie's past comes knocking on their door in the form of Alex Dimitri (Bradley Cooper), the psychotic dreadlocked criminal who Charlie put in jail with his testimony. Thus ensues an extended chase that puts Charlie and Annie's relationship to the test, especially when it's revealed Charlie was more than just a witness to the robbery.

The plotting throughout the entire film is sloppy at its best. Shepard's script (he also co-directed with David Palmer) doesn't get around to telling the audience about Charlie's place in the Witness Protection Program until well into the movie, making much of what came before needlessly confusing. Other characters, including Annie's drug addict boss, overbearing ex and his gay cop brother, fade in and out of the story at random, not that they are contributing much.

Arnold is especially useless, only functioning as a walking punch line. He bumbles through "Hit & Run," mindlessly firing his gun and crashing his car in every other scene. He's also involved in a comic subplot with the gay cop and an iPod app called Pouncer that helps locate other gay men. It bears no relevance to the main story, however, and doesn't get enough laughs to merit its existence.

Its only use is to muddle a story that isn't even quite sure what kind of movie it wants to be. A few intimate moments between the young couple are sweet and light, but they're jarringly interrupted by moments of crass, unpleasant and unfunny humor. Rape, gay people and naked senior citizens are all considered comedic gold for "Hit & Run."

One extended sequence involves Dimitri explaining that he was raped in jail and Charlie attempting to guess the race of the assailant. I ask once again: Was that supposed to be a funny scene? Another scene with Annie dissecting Charlie's use of a derogatory word for gay people could've been a serious scene or just another failed attempt at comedy. Considering the film's inconsistent tone and lack of balance, it could be either one.

In addition, there's a number of car chases scattered throughout "Hit & Run." If you're a massive gearhead, there might be some enjoyment in these scenes. Otherwise, they all play like variations on a theme of cars doing doughnuts and spinning out. Considering the quality of the rest of the movie, it's hard not to think Shepard's script exists solely to put himself into as many cool vehicles as possible.

It's unfortunate because Bell and Shepard seem very pleasant together, both in real-life and on screen. The two have a sweet chemistry together that makes the film occasionally watchable. Those brief moments of genuine charm, however, are crushed underneath "Hit & Run's" scrapheap of meandering plot developments, useless characters and crude, ugly humor. Hopefully, the couple can survive the "Gigli" they've inflicted upon the public.