Corridoring a Roundabout Part 1

Hi everyone. So after playing around the intersection feature and roundabouts I came up with many different ways to corridor roundabout. I think we can all agree that every roundabout will unique in its own way. There are many stipulations that influence the design  of the roundabouts, such as traffic flow, ADA, HOA, and drainage flows. Anyways, what I will show yall is just ideas of what you can do to design and corridor your roundabout. Just remember that the more assembly you use to create your corridor, the more memory it will have to use to regen and rebuild you corridor and surface.

PROCEDURES:

1. Create centerline alignments for the left and right side of the roundabout. Begin your alignments at the begin of your PC of your curb returns. Since my main road travels South to North I designed my roundabout alignments to follow the same directions to make it simple.

2. Now create profiles for both alignments. The beginning and ending elevation will need to match the main roads elevation.

3. Now we need to create assembles that we can use for this sections. As you can see below, I only used 3 types of assemblies.   (I used 2% cross slopes for my pavement)

4. Now we need to create 4 polylines that our road section can target to. These 4 polylines need to start and end at the centerline of our main road. These polylines will be the inside/outside edge of pavement for our road, which we will target.

5. Next will build our corridor. Go into your corridor properties and created 2 baselines (Left and right roundabout) For the right side alignment use the roundabout right assembly Then for the left alignment we will used the roundabout left and intersection assemblies.

As you can see I targeted the polylines.

I didn’t corridor the center of my roundabout because my surface will grade across automatically. (Plus the center is grass)

So that concludes part 1. In Part 2 I will use the intersection feature to corridor the remaining part of the corridor. In Part 3 we will work on the surface editing. Thank you stopping by. Please feel free to make comments or email me.