The objectives of this study are to demonstrate the feasibility and potential effectiveness of using passing lanes in Missouri, to evaluate the level of service and safety effects of existing passing lanes in Missouri, to establish criteria for determining where passing lanes could improve level of service and safety on Missouri highways, and to develop recommendations for the design, signing, and marking of passing lanes for potential application in Missouri. This report addresses the traffic operational and safety effectiveness of passing lanes as well as the geometric design and effective signing and marking of passing lanes. An evaluation of three existing passing lane sites on Missouri NHS routes found that those passing lanes improve percent time spent following on those roads by 10 to 31 percent in comparison to a conventional two-lane highway without passing lanes. A safety evaluation found that the accident frequency per mi per year within passing lane sections on two-lane highways is 12 to 24 percent lower than for conventional two-lane highway sections. Criteria to determine where passing lanes could provide level of service and safety benefits on Missouri highways are presented. Case studies of locations on five Missouri NHS routes examined the potential traffic operational and safety effectiveness of alternative passing lane configurations. (Author/publisher)
Abstract