Joy Ride (2001)

AKA: Road Kill (2001)
Genre: Action | Horror | Thriller
Starring: Paul Walker, Leelee Sobieski, Steve Zahn, and Ted Levine.
Tagline: Don't screw with people you don't know

Plot: Three young people on a road trip from Colorado to New Jersey talk to a trucker on their CB radio, then must escape when he turns out to be a psychotic killer.

http://www.imdb.com/title/tt0206314/
http://en.wikipedia.org/wiki/Joy_Ride_(film)

Sequal: Joy Ride 2: Dead Ahead (2008)