Join Eric Chappell for an in-depth discussion in this video Analyzing open-road site distance, part of Roadway Design: InfraWorks 360.
- Safety is a key consideration when designing a road. And one of the most important factors is sight distance. Roadway design for InfraWorks 360 has powerful tools for assessing sight distance performance. Let's see how they work for an open road situation. I've opened the Lynda Road model, and chosen the Open SD, SD for sight distance, proposal. I'll make a copy of that by clicking Create New Proposal, and I'll call this My_Open_SD.
I'll choose the Lynda Road bookmark, which gives me a 3D view of the road. And then I'll launch the Sight Distance tool. To do that, I'll expand the roadway design toolbar, click the Review icon, and then click the Sight Distance icon. When I do, it opens the Sight Distance dialogue, where I can then select a road for editing. You may have been wondering in the previous videos where would you want to turn off Edit Mode? And this is actually a good opportunity to do that.
If I turn Edit Mode on, you may get gizmos and other graphical elements that kind of clutter up what you're looking at for the sight distance analysis, because as you're about to see there are lots of visual aspects to the analysis. So I'm going to exit Edit Mode whenever I do a sight distance analysis. Now that I've got the road selected, I can make some choices about how I want to perform this analysis. I'd like to look at the road for passing sight distance. Maybe I'm considering having a passing zone on this stretch of road, and I want to see how it will perform.
I'm going in the forward direction, and I'm on lane one. And there's only one lane in this direction, so there aren't any other choices. If I had a multi-lane road, four lane road, let's say, there would be a lane one, and lane two choice here. So I'll go ahead and click Analyze, and see what I get. And what I find is that the road fails for passing sight distance. here at the beginning. And if I switch directions, and analyze backward, or from north to south, I find that it fails on the curve.
Here you can see we've got a sight failure, and some other things going on. So without getting into too much detail about the results we're seeing, we know that this road isn't going to perform well in a passing situation. So let's just scrap that idea, and look at stopping sight distance. So I'll change my analysis to stopping sight, and I'll go to forward again, click Analyze, and in this case, I'm all clear. You can see that I've got this light blue color throughout the entire stretch of road.
I'll switch directions, run the analysis again, and I've got the same thing in the opposite direction. All clear for the full length of the road. But now I realize something. I'd intended to put a bridge in this location. So what does the bridge do to my sight distance analysis? Does the bridge itself provide a sight distance obstruction? Let's find out. I'll go back into Edit Mode, I'll right click, and select Edit.
Make sure my Edit Mode is set to Style on the road asset card. And I'll click the bridge style zone. On the style property, I'll click the value that's there now, and change it under the Street Interstate menu to this one here, Bridge 2 Lane. Click OK, and now we've applied a bridge to our model, just like that. So what does that do to our sight distance analysis? I'll exit Edit Mode, bring up the Sight Distance tool once again, run my analysis, and now we see that the bridge does in fact create a problem.
Let me switch directions to Forward, and we see that in this location, it actually places a pin, showing us exactly where the first problem occurs. And I can even zoom into that location and try to simulate what a driver would see. And I can see how this bridge reel is obstructing the view of a car that might be stopped, or some other obstruction that might be on the road at this location. And what this is telling me is that based on my design speed, I don't have enough distance to stop in to be safe and not have an accident.
Hence, an accident zone in this location indicating that based on my design speed, and the geometry of the road and the obstructions of the bridge, this is a place where I'm likely to have an accident if there's an obstruction in the road. Extremely powerful visual analysis which tells us in a very short time exactly how this road performs. Now we've got other options as well, if we want to look at a specific location on the road, we can place a sight pin. So if I want to analyze exactly what am I seeing from this location, we can place the sight pin and see sight regions, sight lines, and a distance line from that location.
And we can control the visibility of all those items as well. We can also control the visibility of sight zones, accident zones, and sight envelopes. A sight envelope is this light blue area you see here. So you've got lots of control over what you see in the analysis. One other option that I failed to mention was the ability to look at road decorations. So if you have road decorations on your design, light posts, utility poles, guard rails, something of that nature, you could include those on your sight distance analysis.
And you can see how, even though the bridge railing is not considered a road decoration, it's actually part of the bridge structure, you can see that InfraWorks has the capability to not just look at the terrain or the surface of the road, but look at other structures that may be projecting up out of the road, or out of the ground as well. So as you've seen, the roadway module helps you to answer important questions about the safety of your road design in a straightforward visual way, and in a very short amount of time.
Now that you know how the sight distance tool works for an open road situation, you can begin using it to assess the safety of your own designs.
- Understand the capabilities of the Roadway Design module
- Converting spline roads to design roads
- Editing with gizmos and Profile view
- Leveraging advanced features such as style zones, intersections, and roadside grading
- Analyzing and optimizing road designs