Dax Shepard had a simple reason for writing and directing the movie "Hit & Run," which opens nationwide on Wednesday.

"This is my version of 'Smokey and the Bandit,'" said Shepard, who stars with his real-life fiancee, Kristen Bell, in the comedy about a couple who leave their small-town life toward the opportunity of a lifetime. "I have a huge fascination with cars and horsepower. So I got my friends together to make this movie."

The couple's road trip gets complicated when a friend from their past (Bradley Cooper, who is Shepard's real-life best friend) and a band of misfits join the action.

Shepard wrote the script in three weeks, took four weeks to prep and shot the movie in six weeks -- all between the hiatus from seasons 2 and 3 of his TV show "Parenthood."

"To be honest, if I would have taken six months to plan this, it probably wouldn't have come together," Shepard said. "It was just easier to get my friends for a short time to make this high-action comedy."

Shepard doesn't just play a thrill seeker in the film. The 37-year-old Michigan native is one in real life. Working 14 years for General Motors in a variety of roles made him a huge car enthusiast.

He and Bell travel the world racing cars, including racing a Porsche 911 together on the wickedly wild Nürburgring in Germany. And Shepard still has some goals, including racing in the Baja 1000 in Mexico.

"We plan our vacations around racing. Not just spectating. But actually doing," Shepard said. "Acting is a means to an end for me. And cars and motorcycles are the end."