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Reference.org
Highway Capacity Manual
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<p>The Highway Capacity Manual (HCM) is a publication of the <a href="/facts/Transportation_Research_Board/8w5oPeIG">Transportation Research Board</a> (TRB) of the <a href="/facts/National_Academies_of_Sciences,_Engineering,_and_Medicine/AdYmBBGV">National Academies of Sciences, Engineering, and Medicine</a> in the <a href="/facts/United_States/P0sCdLe5">United States</a>. It contains concepts, guidelines, and computational procedures for <a href="/facts/Computing/Kghtm9fX">computing</a> the capacity and quality of service of various highway facilities, including <a href="/facts/Freeway/gaKATAGS">freeways</a>, <a href="/facts/Highway/2nxmEmgX">highways</a>, <a href="/facts/Arterial_road/4a9AfQ7p">arterial roads</a>, <a href="/facts/Roundabout/ubzKqs7N">roundabouts</a>, <a href="/facts/Traffic_signal/v5pwcfsQ">signalized</a> and <a href="/facts/Uncontrolled_intersection/lgenHY6n">unsignalized intersections</a>, <a href="/facts/Interchange_(road)/QMSHwNhF">interchanges</a>, rural <a href="/facts/Highway/2nxmEmgX">highways</a>, and the effects of <a href="/facts/Mass_transit/DXhqazz5">mass transit</a>, <a href="/facts/Pedestrian/Vc8a4xer">pedestrians</a>, and <a href="/facts/Bicycle/nxBVrlBF">bicycles</a> on the performance of these systems. </p><p>There have been seven editions with improved and updated procedures from 1950 to 2022, and major updates to the HCM 1985 edition, in 1994, 1997 and 2015. The HCM has been a worldwide reference for transportation and traffic engineering scholars and practitioners, and also the base of several country-specific capacity manuals. The most-recent version, the <i>Highway Capacity Manual, Seventh Edition: A Guide for Multimodal Mobility Analysis</i> was released in January 2022. Before that HCM 2016 or HCM6, was released in October 2016. The latest edition incorporates the latest research on highway capacity, quality of service, <a href="/facts/Active_traffic_management/mmDwCgaP">active traffic</a> and <a href="/facts/Transportation_demand_management/y7PL1bc2">demand management</a>, and travel time reliability. </p><p>The Sixth Edition of HCM consists of four Volumes. Three volumes are available either in hard copy or PDF, whereas Volume IV is only available online. Volume IV of HCM is free, only requiring readers to create an account in <a href="https://hcmvolume4.org/">hcmvolume4.org</a>. </p>