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Michael Kinnear/5 min read

Modifying Assemblies for Improved Intersection Design: A Step-by-Step Guide

Intersection Assembly Workflow

1

Open Assembly

Edit existing assembly or create a new one for the intersection.

2

Adjust Sub-Assemblies

Modify lane widths, turn lanes, and curb returns.

3

Add Special Conditions

Median, turn lanes, or pedestrian features.

4

Test in Corridor

Apply to corridor and verify cross-sections look correct.

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This tutorial walks through modifying assemblies for improved intersection design, covering essential tools and techniques for your projects.

So in this video we're going to go ahead and modify a couple of assemblies that are associated with the intersections that we have created. If we zoom in here we're going to notice that the curb returns don't look quite right and then this half of our dev intersection doesn't look quite right.

So to fix these what we need to do is we need to first create a half roadway alignment or a half roadway assembly for our intersection here. So what I'm going to go ahead and do is I'm going to navigate over to where our dev assembly is. I'm going to go ahead and copy it and then I'm going to change it based on what needs to happen for this side of the road.

So I know that this road is being read this direction. This is the Left-hand Side so I want to retain the Left-hand Side of my assembly. So I'm going to go ahead and go to this new assembly here.

I'm going to go ahead and retain this left side so I'm going to highlight everything on the right side and I'm going to erase it. So from here I'm going to select the baseline. I'm going to go to Assembly Properties.

I'm going to go to the name and I'm going to go to dev-half. I'm going to go ahead and hit apply and hit okay and then the other change that I'm going to need to make is I'm going to need to make a change to the assembly that's being used for the curb return here. When we created these intersections Civil 3D automatically imported many assemblies up in this corner up here.

If I go ahead and zoom in here each of these assemblies is given a title down here primary road full, we have secondary road full, we have Curb Return Fillets. So this is the assembly that we need to modify. So I'm fine with the lane that we have here.

The curb does not match the curbs that we have in our current drawing so I'm going to go ahead and change this curb. This cut slope is fine but we do need to add in a sidewalk. So what I'm going to go ahead and do is I'm going to pull up my Tool Palettes.

I'm going to go ahead and start by doing a sidewalk addition. So I'm going to go ahead and go Basic Sidewalk. I'm going to click it at the back of the curb here and then I'm going to move this to this point here.

So I've now created this sidewalk and our sidewalks had the standard parameters so we didn't need to modify anything here and I'm going to go ahead and add in a curb now and then I'll delete out this curb. So I'm going to go ahead and add in a Basic Curb and Gutter. I'm going to go ahead and place it at this point here so we'll see that we have two curbs placed here.

I'm going to go ahead and select this curb and do e for erase and then I'm going to have to move this back out. So I'm going to move it out to the top point of this curb. I'm going to have to move this out to the top point of the sidewalk.

For some reason my snaps weren't working quite right so I had to zoom out and zoom extents. I'm still running into an issue with this not selecting into the correct location so what I'm going to go ahead and do is move it further away and then try and move back in. Now I have an ability to snap here so I'm clicking in I'm snapping on this end point right here.

So I've now updated this Curb Return Fillets to have the correct curb the correct sidewalk and then moved the Cut Slope layout moved out. So I'm going to go ahead and close this window and when I do that and I zoom out and go over to our intersections what we're going to notice when I go to my corridor is I'm going to go ahead and select this corridor. I'm going to go to Corridor Properties and I'm going to go ahead and change this Primary Half Road.

I'm going to just go down I'm going to select my assembly my Dev Half and hit okay and hit apply and hit rebuild. And so when I rebuilt that it rebuilt the entire intersection here so what I need to do now is I need to drop into corridors. You're going to see that all of these are out of date.

I'm going to go ahead and select corridors right click rebuild all. So here he's going to rebuild all of the corridors and so what we're going to notice here now is that this half of the roadway matches up with everything that's going on here and we now have sidewalks coming into these corners. However you're going to notice that we now have Bowties.

So I'm going to go ahead and save this drawing and then in the next video we're going to go ahead and clear out these Bowties.