CENTER FOR TRANSPORTATION STUDIES RESEARCH PROJECT PROPOSAL Research Project Title: DYNAMIC ESTIMATION OF FREEWAY WEAVING CAPACITY FOR TRAFFIC MANAGEMENT AND OPERATIONS, PHASE II Principal Investigator Information

Understanding the behavior of weaving flows and estimating the effects of time-variant traffic conditions on the capacity of weaving areas is of critical importance in developing effective operational strategies, which can achieve the maximum utilization of existing capacity for a given freeway system. The previous phase of this research identified and classified the major weaving areas in the Twin Cities' metro freeway network. Further, the traffic behavior and the factors affecting capacity in a type A ramp-weave section, the most common type of weaving areas in the Twin Cities' metro freeways (119 out of 226), were analyzed and an on-line model was developed to estimate the time-variant capacity of type A ramp-weave sections. The proposed research will expand the previous work by testing and refining the on-line estimation model with expanded data set. The variation of Effective Weaving Zone, identified in the previous phase, will also be modeled and tested with real data. In addition, the incorporation of the on-line capacity model into the current ramp metering algorithm will be studied. Finally, the traffic behavior of multi-lane ramp-weave sections will be analyzed and the variation of capacity in those areas will be modeled with data from selected weaving sites. Twin Cities freeways are managed to provide advantage to transit and carpool passengers during peak traffic periods. The meters are intended to keep the freeway lanes moving through bottleneck areas at 30 mph or faster. Meter bypasses are provided at key ramps for buses and carpools. Typically weaving zones are the bottlenecks that are used to control metering rates of the upstream ramp meters. Better understanding of weaving zones will allow better traffic service and management for all cars (reduced ramp meter wait times). Also better understanding of weaving zones will allow for better traveler information for all travelers regardless of mode. Research Objectives The major objectives of the proposed research, phase II, include, • Expanded testing and refinement of the on-line capacity estimation model developed in Phase I, • Modeling variation of Effective Weaving Zone in Type A weaving areas, • Studying incorporation of the on-line capacity estimation model into metering algorithm, • Analysis of traffic behavior and modeling capacity variations in multilane ramp-weave areas. Summary of Previous Work The previous phase of this research has focused on addressing the traffic behavior and capacity issues in a type A ramp-weave area, where a pair of on-and off-ramps are connected by …