Two cars collide on the FDR expressway. Their drivers--two seemingly opposite men--are Gavin Banek (Ben Affleck), a young white partner in a powerful law firm, and Doyle Gipson (Samuel L. Jackson), a meek, working-class black man. At the scene of this fender bender, Gavin, who is busy trying to make a business appointment on his cell phone, offers Doyle a blank check to cover damages. Doyle, wanting to properly exchange information, declines, causing Gavin to flee the accident site. In his haste, Gavin leaves behind an important legal file which Doyle uses to his advantage, setting off a brutal cycle of revenge between these two men who began this Good Friday as strangers.

A class commentary that is decidedly different from director Roger Michell's previous film, NOTTING HILL, CHANGING LANES provides very little information about its two central characters before the moment of their car accident. Michell introduces them by crosscutting between both men speaking publicly--Gavin is lecturing to a charitable foundation, Doyle is talking at an AA meeting. These techniques of crosscutting and mirror imaging are used effectively throughout the film to underscore that the obvious social and economic differences between the two men doesn't disguise the dark and angry nature that exists in both of these men, and potentially in all of humanity.