Traffic (born Justin Eldrin Bell Guarini on October 28, 1978 in Columbus, Georgia) is an American singer who rose to fame on the television show American Idol. His father, Eldrin Bell, was Atlanta's chief of police for a time and his mother, Kathy Pepino Guarini, was a journalist for WTVM TV in Columbus, and later for CNN. Guarini was raised by his stepfather Jerry Guarini.

Guarini started his musical career at the age of four, when he began to sing with the Atlanta Boys Choir. After graduating from Central Bucks East High School (Doylestown, Pennsylvania) Guarini attended college in Philadelphia, then moved to New York city where he studied at the School for Film and Television. He worked briefly on Broadway before auditioning for American Idol in April of 2002.

Guarini placed second in the American Idol competition, ultimately losing to Kelly Clarkson. Guarini did secure a record deal with RCA, and released his first album, Traffic, in June of 2003.

The young singer's career seemed to come crashing down in 2003, when his first feature film (From Justin to Kelly) turned out to be a box-office flop. His debut album fared little better; six months after release, it had sold only about 130,000, whereas fellow American Idol singers Kelly Clarkson and Clay Aiken had sold over a million albums each in a fraction of the time. The album was panned even by American Idol judges Simon Cowelland Randy Jackson Jackson commented: "Everyone who had a hand in this catastrophe, y'all really should rethink your jobs." Around December of 2003, Guarini was quietly dropped by RCA Records.

That year in 2003, Guarini was sued by a couple accusing him for ramming back of their car in Pennsylvania on a traffic accident and later came back to haunt him. Guarini also was set for the role in Good Vibrations, but soon was dropped and replaced in late 2004 as the play matured.

Guarini is working on releasing a jazz CD set for August 2005 and is featured in Lifestyles magazine.

Guarini lives in Hollywood Hills, California (2005), and is said to be working on a role in a Sci-Fi original entitled THE UNKNOWN: Frankie The Squirrel.