SALEM, Va. (AP) _ Highway crews are changing traffic signals on left-turn lanes at 91 intersections in parts of central, southwestern and southside Virginia. The Department of Transportation says the new signals will use flashing yellow arrows to advise drivers to yield to oncoming traffic before turning left. The department says the flashing arrows are more effective than circular green lights in conveying the need to yield. The signals will replace green lights at intersections in Amherst, Appomattox, Bedford, Buckingham, Campbell, Franklin, Halifax, Henry, Montgomery, Patrick, Pittsylvania, Prince Edward and Roanoke counties. The department says the $1.6 million project begins next week and is expected to be completed before the end of the year.