Add Mini-Circle

Add a mini-circle or mini-roundabout.

This function allows you to add a mini-circle or mini-roundabout to the roads design. You can add either a three way or four way circle.

A mini-circle has the following properties:

• Only three or four incoming legs.

• Circular only.

• Consists of a main road running through the mini-circle, with one or two roads intersecting the main road.

• Is modelled as two adjacent junctions, with the circle "draped" onto the junctions. The inner strings are then graded.

• Radii, lane width and crossfalls must be specified.

• Kerb lines are always circular and tangential to the circle.

Procedure

1. You are prompted to:

Indicate first Intersecting Road as close to the Roundabout position

2. Click on the centre line of the intersecting road as shown below:

3. The intersecting road is highlighted and you are prompted to:

Indicate Main Road for the Roundabout calculations

4. Now click on the centre line of the main or through road as shown below:

5. You are prompted to:

Indicate second Intersecting Road for the Roundabout (Esc for 3-way)

6. You can now continue to define a four way circle by indicating the second intersecting or incoming road; or press [Esc] to define a three way traffic circle.

4 Way Circle

1. The second incoming road is highlighted and the Mini-Roundabout Setup displays.

2. Type in the parameters you require and select the Centre Island option.

3. Click OK to add the circle to the design as shown below.

3 Way Circle

1. The Mini-Roundabout Setup looks like this.   

2. The final 3 way circle design displays as below:

The mini-roundabout can be changed at any time using the Edit Junction function. It can be deleted using the Delete Junction function.