METHODS OF SIGNALIZING LEFT-TURN MOVEMENTS AT CHANNELIZED INTERSECTIONS

THE TYPE OF TRAFFIC SIGNAL INDICATION THAT WILL CONVEY TO A DRIVER THAT HE MAY TURN LEFT BUT THAT HE MUST ALSO YIELD TO OPPOSING TRAFFIC WAS STUDIED. THREE TYPES OF INDICATIONS WERE TESTED: FULL GREEN BALL, FLASHING AMBER BALL, AND FLASHING RED BALL. IT IS CONCLUDED THAT THE FLASHING AMBER INDICATION SHOULD BE USED FOR LEFT-TURNING TRAFFIC DURING 2- PHASE MODE OPERATION AT ANY SIGNALIZED INTERSECTION THAT HAS: (1) EXCLUSIVE LEFT-TURN CHANNELIZATION OF SOME TYPE, (2) MULTIPLE OR LANE CONTROL TYPE SIGNAL INDICATIONS, AND (3) A PERMISSIVE OR DRIVER OPTION LEFT TURN SIGNAL PHASE. /RRL/