NCHRP Research Report 1094 presents a deterministic methodology for evaluating the operational performance of weaving sections on arterials. This methodology is based on field data supplemented by microsimulation and driving simulation data and extends the urban streets analysis of the existing, Sixth Edition of the Highway Capacity Manual (HCM6). Accompanying the methodology is a computational engine for implementing it and instructional materials for disseminating it. Two case studies are also provided to illustrate the methodology, which should be of interest to state departments of transportation and other agencies seeking to reduce weaving-related crashes and conflicts on arterial roadways.
Arterial roadways are crucial links in the national transportation system. Providing both local and regional mobility and access, they are critical to economic vitality and quality of life in the United States. As drivers place increasing demands on transportation infrastructure and freeway congestion continues to increase, arterials have become an alternative route for many drivers, resulting in the lower performance of these roadways. In many areas, weaving maneuvers negatively affect arterial operations and safety. Furthermore, weaving maneuvers can affect the operations and safety of many alternative intersection configurations, including median U-turns and restricted crossing U-turns. Understanding the operational and safety performance of arterials and the effect of weaving thereon is important for transportation agencies tasked with maintaining these roadways. The HCM6 provides a methodological approach for estimating the performance of weaving sections on freeway segments. This methodology, however, is not applicable to arterial weaving due to differences between freeways and arterials in traffic control, traffic flow characteristics, and driver behavior.
Under NCHRP Project 15-66, “Operational Performance and Safety Effects of Arterial Weaving Sections,” the University of Florida was asked to (1) develop a deterministic methodology for evaluating the operational performance of weaving sections on arterials and (2) identify the safety effects of varying geometric, volume, and traffic control conditions in weaving sections on arterials. The methodology and analysis are based on field data supplemented by microsimulation data and driving simulation data. The operational analysis methodology extends the HCM6’s urban streets analysis and is based on the calculation of Potential Conflict Opportunities and the Turbulence Index of the arterial weave. The project developed a computational engine which implements the new procedure, along with instructional materials for disseminating the methodology and two case studies. The safety analysis was based on both crash data and conflict data obtained in the field and in the driving simulator. The analysis concluded that as the weave length increases, the chance of weaving-related crashes and conflicts decreases.
In addition to NCHRP Research Report 1094, three deliverables are not included in the published report but are available on the TRB website at trb.org by searching for NCHRP Research Report 1094. The deliverables are as follows: (1) a computational engine; (2) two case studies; and (3) instructional materials.
