Rule-Based Road Design using AutoCAD Civil and AutoCAD Civil 3D

AutoCAD Civil 2009 and AutoCAD Civil 3D 2009 possess the ability to analyze your road design as you work based on recognized industry standards or your own user-defined standards. As you build your design, the software will provide correction and/or notification whenever standards are not met. This capability helps provide many benefits including greater time savings, reduced rework due to fewer review comments, and more consistent quality designs. This is made possible through design checks and design criteria file. Through design checks and design criteria files, you are able to construct dynamic criteria-based geometry. Beginning with the alignment, you can assign design criteria to the horizontal geometry of the centerline helping to ensure that minimum radius criteria are met based on design speed. Design criteria can then be assigned to superelevation settings, a property of the alignment-establishing cross-slopes throughout the design based on design speed and curve radii. Finally, design criteria can be assigned to the profile, also a child of the alignment- establishing minimum K values based on required stopping, passing, and headlight sight distance derived from design speed. These relationships and the associated design criteria result in a comprehensive, criteria-based model that will respond dynamically with each design change. By leveraging these capabilities you will be able to produce sound designs more accurately and efficiently while helping to reduce the need for redesigns that address comments or design flaws. AutoCAD Civil and AutoCAD Civil 3D come equipped with AASHTO-based design criteria files and templates containing common design checks. For those working outside the United States, additional design criteria files can be obtained through country kits at www.autodesk.com/civil3d-countrykits. This content can be used as-is or modified to suit the needs of your designs. The goal of this document is to help equip you with sufficient information about design criteria files and design checks so that you can begin creating your own criteria-based designs, and gaining the benefits of this powerful capability.