State transportation officials are planning changes along a busy section of Route 1A in Holden that has been the site of traffic jams and crashes in recent years. The work would expand two sections of Route 1A, totaling about 1.5 miles, to include two travel lanes and a center lane for drivers turning left from either direction, according to Ted Talbot, a spokesman for Maine Department of Transportation. Right now, the road includes two lanes with no center lane.