TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 105 is the contractor’s final report on the research activities used to develop NCHRP Report 581: Design of Construction Work Zones on High-Speed Highways. NCHRP Report 581 explores an approach for the selection of an appropriate construction work zone type; offers suggested guidance for the design of geometric features, including horizontal and vertical alignment, cross-sectional features, and barrier placement; and examines a variety of ancillary features such as drainage systems, lighting, and surface type. As part of the research associated with this activity, a work zone prediction model and user's guide was created to help estimate free-flow vehicle speeds through two types of construction work zones on four lane freeways--single lane closures and median crossovers.