The edge of the intersection can be defined in two ways:

Enter Curves and Tapers

You can specify just a centre radius, or a centre radius with either a curve or taper lead in and lead out.

Lead In

Option

 

Description

Curve

Select this checkbox to specify a transition curve as the lead-in to the intersection curve.

The schematic layout is updated to show the radius and offset positions.

Taper

Select this checkbox to specify a taper as the lead-in to the intersection curve.

The schematic layout is updated to show the taper and offset positions.

Radius

Enter the radius of the lead in curve. Only available if the Lead in Curve checkbox has been selected.

Taper

Enter the taper ratio as 1:x. Only available if the Lead in Taper checkbox has been selected.

Offset

Enter the distance from the point of edge intersection where the specified curve or taper should begin.

Grade

The grade of the road at this location with the convention that at every point, facing into the intersection, negative grade is down and positive grade is up.

Centre

Option

 

Description

Radius

Enter the radius of the central arc of the intersection edge.

Lead Out

Option

 

Description

Curve

Select this checkbox to specify a transition curve as the lead-out to the intersection curve.

The schematic layout is updated to show the radius and offset positions.

Taper

Select this checkbox to specify a taper as the lead-out to the intersection curve

The schematic layout is updated to show the taper and offset positions.

Radius

Enter the radius of the lead out curve. Only available if the Curve checkbox has been selected.

Taper

Enter the taper ratio as 1:x. Only available if the Taper checkbox has been selected.

Offset

Enter the distance from the point of edge intersection where the specified feature should end.

Grade

The grade of the road at this location, with the convention that at every point, facing into the intersection, negative grade is down and positive grade is up.

Edge Conditions

Option

 

Description

Vertical grading

Set this option to control the vertical smoothing of bell-mouths. It can be set to one of the following:

  • S-Curve - This is the default setting and will apply an s-curve smoothing.

  • Linear - Select this option to apply a linear smoothing between the start and the end of the bell-mouth.

  • From CAD Entities - This option is only available when Extract from CAD Entities is selected, and will use the heights from the CAD entities.

Apply Kerb

Select this checkbox to apply a kerb on this edge of the intersection.

Select Kerb button

Click to display the Kerb Selector and specify a kerb type.

Right (Left) Island

Option

 

Description

Divider Island

If this checkbox is selected on either the left or right side, the Centre Island Page will be disabled.

Island Type

Select the island type from the list. There are two types:

  • Enter Radii and Widths - Specify the radii and widths in the Island Settings.

  • Extract from CAD Entities - Indicate polylines on a drawing.

Apply Kerb

Select this checkbox to apply a kerb on this island.

Select Kerb

Click to display the Kerb Selector and specify a kerb type.

Extract from CAD Entities

  1. Click Indicate to display the main drawing. You are prompted to indicate the polylines that define the left or right intersection curve:

Extracting 'Left Bell Mouth' from CAD: Select Entity

  1. Select the entities that define the bell mouth.