Create Junctions
From the series: Getting Started with RoadRunner
Demonstration of creating complex junctions in RoadRunner interactive editor.
Published: 19 Sep 2024
Hello, this is Aidan. This video covers junction creation in RoadRunner. To start with, we're going to use the Road Plan tool to generate a road. Right-click to set the start point for your road. Right-click again to draw the rest of it. You can add additional points to your road by right-clicking anywhere on it. In this case, let's make a nice, simple curve. Now let's draw a second road that does not quite attach to it. We're going to use this to demonstrate the Slip Road tool.
The Slip Road tool can be used to make more specialized junctions. Simply right-click on the edge of this lane and drag to generate a lane that connects over to here on the main road. You can also right-click and drag from the edge, but not connected to the other road. This unattached lane can then be manipulated as per a normal road using the Road Plan tool. This will give you more freedom in road position compared to automatically connected road. So it's important to decide which version of this you want to use.
You can also click and drag from anywhere else on a road to generate a slip road like so. These slip roads are automatically attached to the lanes they connect to and cannot be wiggled around and manipulated like the ones that were not generated. Slip roads that are built by connecting one road to another are attached to those roads. You can move them around, but you cannot pull them away from these roads.
Next, let's talk about the Marking Point tool. To start, we're going to go to the Stencils folder and find markings appropriate for the junction we've just created. Simply click and drag the marking out into the scene and you will see that it snaps to any existing lanes. Simply let go of it and it will attach in that place. You will also find that I'm now toggled into the Marking Point tool automatically by dragging that out. Once a marking is attached in this way, I can click on it and drag it around within its lane.
Now I'll add another marking over here so that this looks like a proper split of lanes. I can also adjust this marking to a larger size by simply clicking on it then dragging the stencil out of the Stencil folder and over that marking. Now let's build a junction with turn lanes. The first thing we're going to do is intersect our existing highway road with another road so that cars have somewhere to turn into and out of.
Next, let's put some space between these two lanes. We're going to do this with the Lane Form tool. So we're going to zoom in, click on this lane, and then right-click and drag, producing a new road. Make sure that this road is approximately the same width as the other two.
Now we're going to make use of the Lane Chop tool. Simply right-click to slice a lane into two parts, each that can be modified separately. We're going to place one a little bit higher up and one exactly where these lanes connect to the highway road. Now we're going to activate the Lane tool. Select the area we just chopped out and change its type to raised median to put a barrier between our two lanes. With the barrier placed, let's add some turn lanes.
We will use the Lane Carve tool to divide this lane. Now we will clean it up so it looks a little more like a turn lane. We're going to go into Markings and grab appropriate markings. We will also add a stencil.
Now we will use the Lane Carve tool on the other side and clean it up. Finally, let's add one more slip road. We're going to adjust this one slightly once we've placed it. By doing this, you can change the shape of your slip roads. Let's do a bit of final tidying up and check maneuver roads.
Now to check maneuver roads, we're going to click on the Maneuver tool and then click on a junction. As you can see, each lane and how it connects to any other lane is displayed here. We can clear out any of these that we don't need by clicking on them and then pressing the Delete key. Here I think this lane can be a little better place so I'm going to stretch it out slightly and then adjust it until it looks like a nice organic curve. And with that, our junction is complete.
Finally, let's make some opposing turn lanes. Now we'll use the Lane Carve tool to make our turn lanes. Just like before right-click the lane and drag to an adjacent lane. Now we'll make sure these lanes face in the proper directions using the Lane tool.
This central section should be set to travel direction Undirected and type Restricted so that no traffic can pass through it. This lane should be set from forward to backward. Now we'll apply stencils. We will finish off this section by applying some residential roads that can connect into our lanes.
And there's this finished junction. The maneuver roads might need a little bit of cleanup so let's check them now. Yes, there are several maneuver roads that shouldn't be there. It looks like the problem is that our lanes are too close and are overlapping, forming these two junctions. We can move the lanes to fix this.
These junctions are now separated, but they still have some excess maneuver roads. Let's trim those now. Here is another way to build another variation of this type of junction. Have the road first this time. Now we'll go in a little bit.
Now we will use the Lane Form tool to add an extra lane to this road. As usual, keep this lane about the same width as your other lanes. Use the Lane Marking tool to adjust this marking so that cars have a spot to get into this lane. Just like before, we will use the Lane Carve tool into Markings, and we will adjust the lane markings.
Let's wrap things up by going to Stencils for some arrow markings. And finally, we will check out the maneuver roads. Everything looks in order here.