ANALYSIS ON OPERATIONAL INTERACTIONS BETWEEN FREEWAY MANAGED LANES AND PARALLEL GENERAL PURPOSE LANES

摘要

Roadway agencies face growing challenges to expand freeway capacity. Under consideration ofrising construction costs, right-of-way limitations, and environmental constraints, transportationagencies are seeking solutions to efficiently manage the demand on existing freeway facilitiesand to provide options for travelers. The concept of managed lanes (MLs) is an increasinglypopular countermeasure that aims to make the most efficient use of freeway facilities, byrestricting access to one or more lanes to certain vehicle classes on a facility that is parallel toexisting general purpose (GP) lanes. With different strategies for separating ML and GP lanes,this study examines the interaction between GP lanes and ML operations. It scrutinizes thiseffect as a function of different separation types, the number of MLs, and operational MLstrategies including high-occupancy toll (HOT) and high-occupancy vehicle (HOV) lanes. Fourfreeway sites were selected to explore this effect. The research shows that for HOT facilities, theseparation type had the most significant impact on explaining the frictional effect intensity, aspaint-separated ML facilities are readily impacted by congestion in the adjacent GP lanes. ForHOV facilities, the frictional effect is observed by adopting a stochastic capacity estimationapproach to estimate the capacity distribution function for both GP lanes and HOV lanes. It isdetermined that GP lanes have a stochastic dominance over HOV lanes under any breakdownprobability. The results make the case that ML operations should not be evaluated independentof adjacent GP lanes, which have implications for proposed analytical approaches, but also forsimulation-based analyses.