Williams' attorney, Jonathan Simon, told ESPN.com that the Florida assistant state attorney determined there was not sufficient evidence and that the evidence it did have refuted the police report.
Williams was arrested April 3 in Tallahassee by the Florida State University Police Department.
According to the arrest report, Williams, whose legal name is Kenneth Williams Jr., was pulled over shortly after 3 a.m. after stopping during a green light at an intersection and then making an illegal left turn even though there was a posted sign prohibiting a turn there. The officer pulled him over after he swerved over the lane divider several times.
Williams, the defensive MVP of the 2013 BCS National Championship, declared for the draft after his junior season.
Mel Kiper Jr. ranks Williams as the fifth-ranked cornerback prospect in this draft, after Trae Waynes of Michigan State, Kevin Johnson of Wake Forest, Marcus Peters of Washington and Byron Jones of UConn.
The first round of the NFL draft begins Thursday at 8 p.m. ET in Chicago.
DUI charges dropped against P.J. Williams
Steve Muench discusses why DUI charges against former Florida State defensive back P.J. Williams have been dropped, and whether his NFL draft stock will be affected.