Update of Highway Capacity Manual: Merge, Diverge, and Weaving Methodologies

Freeway congestion usually occurs at freeway merge, diverge, and weaving segments that have the potential to develop bottlenecks. To alleviate or mitigate the impacts of congestion at these segments, a number of active management operational strategies have been implemented such as ramp metering, hard shoulder running, managed lanes, and others.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 1038: Update of Highway Capacity Manual: Merge, Diverge, and Weaving Methodologies develops methodologies to update the HCM related to merge, diverge, and weaving methodologies and pilots the developed methodologies to demonstrate the full range of applicability of the proposed updates to the HCM.

Supplemental to the report are NCHRP Web-Only Document 343: Traffic Modeling Document; proposed revisions to Chapters 13, 14, 27, and 28 of the HCM; a presentation summarizing the research; and spreadsheet-based computational engines implementing the proposed methods.

See also: Highway Capacity Manual 7th Edition (2022).