This Circular presents what is expected to be the final text for portions (Chapters 3, 5, 7, and 10) of the Third Edition of the Highway Capacity Manual. It is presented in an effort to make new procedures available to practitioners as early as possible, and also to provide an opportunity for review so that problems will be minimized in the final publication of the Manual in 1985. Three of the Chapters (3, 5, and 10) represent revisions and updates of material contained in TRB Circular 212, "Interim Materials on Highway Capacity." "Basic Freeway Segments" replaces the section (Chapter 3) with the same title in The Highway Capacity Manual. "Ramps and Ramp Functions" replaces another section similarly titled in the freeway capacity procedures. The procedures in "Unsignalized Intersections" is also replaced by the section presented in this Circular. New material is presented on the procedures for multilane highways.