Sample Drawing for Intersections and CuldeSacs


Every time I teach a Basic Civil 3D class, I get the comment “So these corridors are great?  But how do I do an intersection? or a cul de sac?”

Putting together an intersection is really pretty simple, but without a little imagination and a kick in the right direction, it can be hard to figure out your first time.





So I’ve put together a quick sample drawing (for member download) and a few screen captures that might help you get going.  This drawing also has some of my “Reference and Expression Design labels” to help you keep track of intersection design changes.





Members of (don’t forget to login) will be able to see a link to download a Sample Drawing below.  Not a member?  Sign up by clicking the “Register” link on the right.

Here is the download for today’s posts about getting started with intersections and cul de sacs.

Keep in mind, this road is not “designed” to work just yet.  I have simply built the model- so that now I could begin my iterations and refinement.  The Model is built to a point that it makes sense and can properly represent my design intent.  Now it is up to me to design it!

Please use this as a GUIDE ONLY to model your own site- I know how hard it is to get started with intersections, and hopefully this will get you going.

More details and more instruction can be obtained from AU papers and AOTC Solutions Series Intersections and Cul de Sacs

Sample Drawing Intersection and Cul de Sac


  1. TimStalin says:

    Nice guide Dana. Thanks for taking the time to educate us as often as you do.

    Do you know if anyone has posted a guide dealing with parabolic road intersections? For the most part it should be similar to straight crossfall roads except there is no half-parabolic sub-assembly. Has anyone created such a SA and willing to share it? Or should I just sit down and learn some VB?

    Also, is the AOTC Intersection guide worth purchasing if you regularly attend the webcasts? I found the Residential Grading guide really just transfered the webcasts into a guidebook form. I’m not complaining about the guide, just stating my observations.

  2. To take minor exception, the webcasts took what we did in the AOTC Residential Grading book and put it online. The books are good in that they both give some background and process information in addition to picks and clicks. Additionally, there are things done in both books that have never been presented in a webcast. Not earthshattering new material, but new none the less.

    Hope this helps some, and thanks for your comments!

  3. MHellerstedt says:

    Could you downgrade your sample file to v2006 for those of us using the old version?

  4. Dana Breig Probert, EIT says:

    I’ve had some requests to put up a sample “holding the main road crown” intersection drawing, so i will do that today.

    here is a caveat to this drawing guys— I MAKE NO PROMISES that this is a good design. I just put together the model in a way that a blended crown intersection would be modeled.

    So no snarky comments about how hard it would be to drive over this. That’s fine. Take my model and design something with it. But if you have a blended intersection- this is how you model it.