Caltrans is working to reduce the support costs incurred during the project development process that span planning/environmental assessment, design, right of way and construction stages. The current process for developing highway infrastructure improvements is to collect location and elevation data in 3-D that is converted to a digital terrain model used in the design of 2-D plans.

The Plans, Specifications and Estimate (PS&E) bid package used by contractors to provide their construction bids includes these 2-D plans. Ideally, the PS&E package should be developed using 3-D modeling. Model-based design has the potential to improve project delivery, enhance preconstruction process reviews, optimize scheduling, streamline construction phasing and communicate project features.

Caltrans is interested in learning how other state departments of transportation (DOTs) are employing 3-D modeling and other types of advanced modeling techniques for developing highway infrastructure improvements. To aid in this effort, this Preliminary Investigation presents the results of a survey that explored the state of the practice in transportation agencies use of advanced modeling. To supplement survey findings, we also examine domestic and international research and federal guidance related to the use of advanced modeling techniques to enhance project delivery.