OpenSCAD - OpenSCAD is a software for creating solid 3D CAD objects.
Civil 3D - Civil 3D supports BIM for civil engineering design and documentation for rail, roads, land development, airports, water and wastewater, and civil structures.
FreeCAD - An open-source parametric 3D modeler
OpenRoads Designer - A detailed design application for roadway, surveying, drainage, and subsurface utilities that supersede capabilities previously delivered by InRoads and GEOPAK
OpenJSCAD.org - OpenSCAD + JavaScript = OpenJSCAD, edit locally or remote online, preview in browser direct via...
Site3D - Site3D is a fully featured software product for the engineering design of road systems, roundabouts, residential developments and earthworks.