Roundabout setup

The Roundabout feature helps you model traffic flow on circular intersections by adding a roundabout object and generating movements automatically.

In the Design workflow, this is available in tab:

• 6. RoundAbount - Manage roundabout and auto movements

When to use Roundabout

Use roundabout setup when:

• You analyze a circular intersection where vehicles enter and leave through multiple approaches

Before You Start

Prepare the scene first:

1. Add and position gates in the Gates tab

2. Set each gate type correctly:

   • Entry = input to roundabout

   • Exit = output from roundabout

   • Bidirectional = both input and output

3. Verify gates are placed close to each approach lane

The gate type decides how a gate is assigned under a roundabout.

Step 1: Add Roundabout Shape

1. Open tab 6. RoundAbount - Manage roundabout and auto movements

2. Click Add

3. On the video frame:

   • First click sets the center of the roundabout

   • Second click sets the ellipse size (radius)

4. The roundabout appears as an ellipse with direction arrows

Step 2: Assign Gates to Roundabout

In the Roundabout list/tree:

1. Expand the roundabout item

2. Check gates that belong to this roundabout

3. AITracker assigns checked gates automatically by gate type:

   • Entry/Bidirectional gates to roundabout inputs

   • Exit/Bidirectional gates to roundabout outputs

Step 3: Generate Movements Automatically

1. Click Generate movements

2. AITracker creates movement relations for selected gate combinations in that roundabout

3. Open the Movements tab to review the generated items

4. Keep only valid movements enabled (selected)

Step 4: Set Correct Rotation Direction

Roundabout movements depend on rotation direction.

1. Check the roundabout(s) in the tree (top-level checkbox)

2. Click Reverse to switch direction:

   • Clockwise -> CounterClockwise

   • CounterClockwise -> Clockwise

3. After changing direction, movements are regenerated for the selected roundabout(s)

Optional: Draw a Custom Movement Through Roundabout

If needed, you can still draw movements manually in Movements mode:

1. Start on an Entry or Bidirectional gate

2. Click through the desired path (optional intermediate points)

3. Pass through the roundabout area

4. Finish on an Exit or Bidirectional gate

This is useful for non-standard geometry or special traffic patterns.

Editing and Cleanup

• Delete: remove selected roundabout by clicking it in image

• Clear: remove all roundabouts from the current configuration

• Removing a gate from the configuration also removes its roundabout assignment

Best Practices

1. Place gates close to physical entries/exits of the roundabout

2. Keep one roundabout object per physical roundabout center

Troubleshooting

I cannot create a roundabout

• Make sure you clicked Add in the RoundAbount tab

• You must provide two clicks: center and ellipse edge

Generated movements look wrong

• Verify gate types (Entry/Exit/Bidirectional)

• Verify which gates are checked under the roundabout

• Use Reverse if traffic circulation direction is opposite

Too many movements were generated

• This is expected when many gates are selected

• Disable unnecessary movements in the Movements table