A new traffic signal at the intersection of U.S. Highway 17 and the entrance to the Georgia Ports Authority Colonel’s Island terminal will be functional starting Thursday, a little more than three years after three port workers were killed there in a crash. The state Department of Transportation has been working on preparing the intersection for the signals since last year. A left turn lane at the exit from the port was added. The light installation was paid for by the DOT and the Ports Authority. The Glynn County Commission approved a measure last December to pay for power to the light.