This is Autodesk's standalone vertical product that includes all base AutoCAD features plus advanced civil engineering tools.

: Design components are managed as Building Information Modeling (BIM) objects, allowing for dynamic updates across the entire project when changes are made. System Requirements for 64-bit Installation

Would you like help finding legitimate civil engineering plugins or free alternatives for specific tasks (roads, terrain, drainage, etc.)?

is a popular software module designed to run as an extension within to automate civil engineering tasks. For AutoCAD 2013 64-bit

Optimized Design: Mastering CivilCAD for AutoCAD 2013 (64-bit)

Here's what you should know: