If the 30-year-old multi-platinum artist and Russaw, 35, complete the 13-week program, the case will be closed, the Atlanta Journal Constitution reported Thursday.
Evans and Russaw were charged with possession of powdered cocaine and less than an ounce of marijuana Jan. 27 following a traffic stop of the silver 2003 Hummer driven by Evans.
The arresting officer smelled "burning marijuana" in the car and found a suspected marijuana cigarette in the ash tray, said Police Captain William Lyons.
Evans also was charged with having an improper vehicle tag, the original cause of the stop.
Evans earned a Grammy nomination for her duet "Can't Believe," and recently appeared in the movie "The Fighting Temptations" with Cuba Gooding Jr. She is the widow of the late rapper known as the Notorious B.I.G., who was killed in a drive-by shooting in 1997 in Los Angeles.