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This is Volume 4 for the HCM 6th Edition, first published in 2016. To access Volume 4 for the HCM 2010, please visit

What is Highway Capacity Manual Volume 4?

The HCM consists of three printed volumes (Volumes 1-3) that can be purchased from the Transportation Research Board. Volume 4 is a free online resource that supports the printed manual. It includes:

Who Can Access HCM Volume 4?

HCM Volume 4 is free to everyone, but registration is required. Sign up now to take advantage of these resources and join the discussion!