Consideration of Bollard Treatment at Exit Gore Areas

The efficiency of bollards—soft plastic post delineators which are installed at exit gore areas of some highways in Israel—is considered. The devices are expected to contribute to better arrangement of traffic streams and to reduce erratic vehicle maneuvers at highway exits. The treatment was examined in three ways: (1) a review of current experience concerning delineation techniques and tools for safety enhancement at exit gore areas, (2) a detailed consideration of accidents occurring on freeways with emphasis on specifics relevant to exit area occurrences, and (3) field observations of driver behavior at exit areas before and after bollard installation. The literature review showed that use of bollards for highway traffic arrangements has not been investigated closely, at least over the past 20 years. However, practice demonstrated that different kinds of delineation treatments did contribute to better traffic operations and decreased the number of erratic maneuvers at exit area approaches. A detailed consideration of accidents for two highways revealed that the accidents occurring at “exit” and “on” areas are a major part of interchange area accidents (69 percent), while explicit “gore area crossing” maneuvers appear only in six cases (23 percent of exit accidents). In total, a potential benefit of bollard application could be relevant to 11 percent of the accidents. Field observations of driver behavior were conducted for two sites. The comparison proved a significant reduction in erratic maneuver rates after the treatment: up to 60 percent in daytime and up to 65 percent at nighttime. Finally, the bollard treatment was recommended for use at freeway exits.