Explore the step-by-step process of creating a highway widening to add a dedicated turn pocket and acceleration lane for a new development. This article provides detailed instructions on how to use Civil 3D's alignment dropdown to create a widening and adjust alignment settings to reach a desired solution.
Key Insights
- The article demonstrates how to add a widening to a highway to facilitate improved traffic flow for a new development. This widening will create a dedicated turn pocket and acceleration lane for vehicles entering and exiting the development.
- The step-by-step guide instructs users on how to use Civil 3D's alignment dropdown to create a widening. It also touches on selecting an alignment and working with widening alignment.
- It underlines the importance of adjusting default settings within Civil 3D to avoid the return of a "no solution" when creating a widening. The article highlights potential issues, such as being near edges, that could lead to this outcome if settings aren't properly modified.
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In this video, we're going to create a widening for our existing highway. The reason we're doing this is that we've been talking about creating this development down here.
As part of this development, we want the traffic from the highway to be able to get over into a dedicated turn pocket and turn onto our main alignment. And then same thing for people coming out of the development, we want them to be able to turn onto the highway into their own dedicated lane, then get up to speed safely and merge into traffic. We're going to be creating a widening on the right-hand side of our road to add in that turn pocket and that acceleration lane.
So from here, we're going to go up to the alignment dropdown. We're going to select Create Widening, and then we're going to select an alignment. Since we are working with our widening alignment, we're going to go ahead and select that widening.
Now, this is one way to get into adding a widening to an offset alignment. There are other ways to do that, and I'll show you how to do that in the next video. But for this one, we've selected widening.
We're going to select the offset alignment that we want to add a widening to, and then we're going to go ahead and select that alignment. So I'm going to pick it. Civil 3D is going to ask me if I want to create the widening portion as a new alignment.
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So I can either create a new alignment or I can make it part of the original alignment. So I'm going to go ahead and say no, do not create a new alignment.
From here, Civil 3D is going to ask me to select a start station.
Now, one thing to consider when you're dealing with alignments and creating widenings is that Civil 3D auto-populates your widening with some set parameters based on your settings inside of your Settings tab. We didn't modify our settings, and so I know those settings may be different from what we're going to end up wanting to generate inside of this drawing. Those settings can have a negative impact on creating this widening by returning us a no solution for our widening.
If we were to pick a start point that's very close to an edge, anytime you're dealing with being very close to edges, and you're adding widenings, and you're not modifying your settings, you may get a return of no solution. That's simply because the parameters that Civil 3D is using when creating that widening don't mesh with the begin or end point of your alignment.
To avoid something like that happening in our current drawing, I'm going to go ahead and pick somewhere not necessarily where I want to start my widening, but just somewhere that I know I'll be able to get a solution. So I'm going to go ahead and select a start station for my widening somewhere over here, and I'm going to pick an end station for my widening somewhere over here.
Now, these are going to be modified in another video. I don't care where I selected, as long as my start station starts at a station that's before my end station. I've done that.
Now what I need to do is make sure that I select a correct widening offset. Because we're basing this widening off of an existing offset alignment, we are not trying to create a widening that is going to be offset off of that offset alignment. That offset alignment calls back to our original parent alignment, which is the center alignment.
The widening that we actually want to create will go out and beyond that 18-foot that we have selected. If I put 18-foot, it would not be 18 feet beyond my widening alignment. It would be out to 18 feet from the centerline.
What I want to do is create an ultimate width of 30 feet. So I'm going to go ahead and offset or choose my widening offset of 30 feet. So I'm going to go ahead and hit ENTER.
What you'll notice is Civil 3D autogenerated a widening in the section that I have selected. Now it's not in the correct location and we can modify these settings, but we're going to do that in the next video. So I'm going to close this window and I'm going to go ahead and click Save and I'll meet you in the next video.
