For many road projects, the engineer must work through several alternatives very early in the process and present them to a seemingly infinite number of stakeholders. They work with transportation planners, local elected officials, other agencies… and of course an endless stream of public workshops, public hearings, council hearings, etc. There are many documents to create- Environmental Impact Studies, Traffic Impact Studies, Regional Planning documents, and more.
A quick internet search led me to some sample exhibits for major projects that provided a lot of food for thought on how we can use Civil 3D to understand each alternative better and give the stakeholders more information to help make their decisions. The MoDOT website had some particularly easy to find exhibits (note that I do not know what they used to create these exhibits, they are just publicly available examples to get ideas from.)
Here are just a few ideas to get us thinking:
I started out with a terrain model. Depending on how conceptual you want to be, you could just grab a surface from Google Earth, download some contour shape data or a DEM, use aerial topography or surveyed information. I created a simple basemap using GIS information. I also made a first draft centerline and used the offset alignment command to make two dynamic 50’ offsets. These represent a minimum distance to utility poles in my case, but could be anything- think about required right of way, drainage offsets, noise buffers, anything that moves with the road centerline.
The resulting model looks like this in plan view:
Here is a closer look:
I built a simple corridor using a typical road cross section- you could start with anything knowing that it will be refined later. Then, I created a code set that hatches everything in the corridor in plan view with solid yellow. I took out the visibility for links, points and feature lines in plan for this code set because I just want to see the limits of the corridor’s impact- and play around with the road alignment to stay within the existing right of way.
As I iterate through horizontal layout, I can get immediate feedback on how my corridor will respond- and where I violate the limits of my existing right of way.
You could also split your view to see plan (or better yet 3D) and profile simultaneously as you work through the options. Note the profile criteria set violation marker in the profile view below. You could also have a mass haul diagram, QTO or volume calculation giving immediate feedback to approximate quantities and impacts at the conceptual stage. Check out the Transportation: Road Design Whitepaper series for more information about building road corridors and using criteria based design.
Since you know that I feel Civil Engineers don’t take advantage of conceptual design enough, I’ll be talking about this more. What are your thoughts? Do you create exhibits and concepts like this? What tools do you use?