IMPROVING SIGHT DISTANCE FROM OPPOSING LEFT-TURN LANES

Sight distance availability is an important factor affecting safe traffic operations at intersections with unprotected left-turn movements. In such situations, drivers must choose adequate gaps in the opposing through traffic stream to complete left-turn movements. These left-turn movements can be further complicated by the presence of opposing left-turn vehicles. The opposing left-turn vehicles can greatly reduce the left-turn sight distance available. The University of Nebraska-Lincoln, in cooperation with the city of Lincoln, city of Omaha, and the Nebraska Department of Roads, is conducting a study to improve opposing left-turn lane sight distances by means of pavement markings. The objective of the study is to eliminate this sight distance problem by using pavement markings to encourage left-turn drivers to position themselves laterally closer to the median, thus improving their view of opposing through traffic. Before and after treatment studies of left-turn vehicle positioning are being conducted. The before study results and the subsequent treatment designs are presented in this paper.