Baltimore Ravens cornerback Tray Walker is in critical condition after a serious dirt bike accident Thursday night, according to the team and police. The 23-year-old was taken to the trauma center at Jackson Memorial Hospital in Miami. Walker was riding a Honda dirt bike without headlights when he collided with a woman driving a Ford Escape, said Det. Dan Ferrin, spokesman for the Miami-Dade Police Department. The woman was not hurt. Police said dirt bikes must have headlights and a license plate in order to ride legally. Authorities said they would continue to investigate the crash. Walker, a fourth-round pick last year, played in eight games with the Ravens during his rookie season.