DRIVER UNDERSTANDING OF THE GEEN BALL AND FLASHING YELLOW ARROW PERMITTED INDICATIONS: A DRIVING SIMULATOR EXPERIMENT

This paper identifies the use of a driving simulator located at the University of Massachusetts to study the green ball and flashing yellow arrow permitted indications in protected/permitted left-turn (PPLT) signal displays. The circular green ball indication is the Manual on Uniform Traffic Control Devices (MUTCD) standard to convey the meaning of a permitted (e.g., left-turn) movement at signalized intersections. A key study task in the National Cooperative Highway Research Program (NCHRP) Project 3-54 research (Evaluation of Traffic Signal Displays for the Protected-Permitted Left-Turn Control) is to evaluate the green ball and flashing yellow arrow permitted indications. This paper presents a brief background on the research project and preliminary results of 211 subjects.