@article{amini_xu_rouphail_elefteriadou_aghdashi_2021, title={Capacity Analysis Framework for Freeway Ramp Weaves}, volume={147}, ISSN={["2473-2893"]}, DOI={10.1061/JTEPBS.0000594}, abstractNote={AbstractThe Highway Capacity Manual 6th Edition (HCM6) provides methods for evaluating freeway segments and facilities, including weaving segments. Recent research has cast doubt on the validity of...}, number={12}, journal={JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS}, author={Amini, Ehsan and Xu, Dezhong and Rouphail, Nagui M. and Elefteriadou, Lily and Aghdashi, Behzad}, year={2021}, month={Dec} }
 @article{xu_rouphail_aghdashi_ahmed_elefteriadou_2020, title={Modeling Framework for Capacity Analysis of Freeway Segments: Application to Ramp Weaves}, volume={2674}, ISSN={["2169-4052"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85085987562&partnerID=MN8TOARS}, DOI={10.1177/0361198119900157}, abstractNote={ This research proposes a new modeling framework for the analysis of freeway segments. The framework provides a continuum from the operation of ramp weave segments to an equivalent basic segment serving the same traffic with the same number of lanes and free-flow speed. This approach distinguishes between congestion effects caused by high v/c ratios from turbulence caused by merging, diverging, and weaving traffic, thus greatly simplifying the model form, and its extensibility to other freeway segment types. The paper presents an application of this new framework to the analysis of ramp weaves, which were not sufficiently sampled in the development of the HCM6 methodology. The proposed model is shown to be superior to the HCM6 method both in relation to explaining field observations of speeds and in its simplicity in application. The results include a new formula for capacity estimation that is highly sensitive to segment length, and a speed estimation model that converges for low weaving volumes or at very high weaving segment lengths to that observed at a basic segment. Because the proposed model is calibrated with data mostly from North Carolina, it is recommended that data at additional sites be included in a larger calibration effort to ensure its applicability to a broader set of weaving segment configurations. }, number={1}, journal={TRANSPORTATION RESEARCH RECORD}, author={Xu, Dezhong and Rouphail, Nagui M. and Aghdashi, Behzad and Ahmed, Ishtiak and Elefteriadou, Lily}, year={2020}, month={Jan}, pages={148–159} }
 @article{ahmed_xu_rouphail_karr_2019, title={Lane Change Rates at Freeway Weaving Sites: Trends in HCM6 and from NGSIM Trajectories}, volume={2673}, ISSN={["2169-4052"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85064555642&partnerID=MN8TOARS}, DOI={10.1177/0361198119841281}, abstractNote={ Concerns have been raised about the HCM6 weaving method’s lack of sensitivity to weaving segment length. This study explores the trends in HCM6 as they relate to lane change estimates and their impact on the segment speed and level of service (LOS). The study also compares HCM6 estimates of lane changes against empirical data from an NGSIM weaving site. Thus, the objectives of this study are twofold: ( a) critically investigate the effect of weaving length on lane change and associated speed model estimates in HCM6, and ( b) analyze trends in lane changes against congestion levels using detailed NGSIM trajectory data, comparing against HCM6 estimates. For ( a) it was found that the lack of sensitivity to weave length is because of the absence of this parameter in the nonweaving lane change and speed models. For ( b), a comparison of HCM6 lane change rates with NGSIM, US-101 data confirmed that the HCM6 estimates for weaving vehicles are fully consistent with those at the NGSIM site, controlling for density. In contrast, nonweaving lane change estimates in HCM6 did not deliver the expected trends, with more discretionary lane changes predicted as congestion increased. Finally, analysis of lane change patterns at the NGSIM site revealed a tendency for early merging for freeway to ramp traffic and uniform merging for ramp to freeway traffic over the length of the weave. Interestingly, a speed analysis showed that in most cases, a higher frequency of discretionary lane changes yielded lower travel times for drivers executing them. }, number={5}, journal={TRANSPORTATION RESEARCH RECORD}, author={Ahmed, Ishtiak and Xu, Dezhong and Rouphail, Nagui and Karr, Alan}, year={2019}, month={May}, pages={627–636} }