TRB's National Cooperative Highway Research Program (NCHRP) Report 826: Estimating Highway Preconstruction Services Costs presents guidance for state departments of transportation (DOTs) and other agencies for estimating preconstruction services (PCS) costs for transportation project development. PCS refers to a varied assortment of project-specific engineering and other professional services required before construction begins on a bridge, highway, or other transportation project, whether provided by agency staff or consultants. Volume 1: Guidebook addresses principal sources and components of PCS costs, PCS estimating methodologies, trends (such as changes in design and construction technology, design standards, program requirements, and professional workforce) likely to affect PCS costs, and advice on agency policies and practices that can help control program risk through improved PCS cost estimation. Accompanying Volume 1, Volume 2: Research Report documents the development, testing, validation, and packaging of an accurate, consistent, and reliable method for estimating PCS costs."--