Two additional design criteria files were supplied with AutoCAD Civil 3D 2015:
- Autodesk Civil 3D Imperial (2011) Roadway Design Standards.xml
- Autodesk Civil 3D Metric (2011) Roadway Design Standards.xml
These files are installed to the following folder by default: C:\ProgramData\Autodesk\C3D 2025\<language>\Data\Corridor Design Standards\<units>.
All numeric values were taken from A Policy on Geometric Design of Highways and Streets, 6th Edition, 2011, commonly referred to as the "Green Book," published by the American Association of State Highway and Transportation Officials (AASHTO).
General
- Minimum radii for non-superelevated roads were added.
- Minimum radii for design speed 10mph (15kph) were added.
Alignment Superelevation
- Superelevation rate for
e
max=2.0 replaced with RC (remove adverse crown) in all superelevation rate tables.
Widening
- Widening: Design vehicle WB-50 (WB-15) has been removed and replaced by WB-62 (WB-19 for metric units) as the standard design vehicle (from table 3-26b in A Policy on Geometric Design of Highways and Streets, 6th Edition, 2011).
- AASHTO Standard Formula corresponds to equations 3-31 (lane width plus lateral clearance factor), 3-32 (vehicle overhang), and 3-33 (additional width allowance) in A Policy on Geometric Design of Highways and Streets, 6th Edition, 2011, and solves for the change in lane width. AASHTO Standard Formula will result in larger values for lane widening.
- AASHTO Simple Formula corresponds to equation 3-31 in A Policy on Geometric Design of Highways and Streets, 6th Edition, 2011, and solves for the change in lane width.