Roundabouts Properties: Arm: Slip Lane: Slip Lane Curve

Click Slip Lane Curve under Slip Lane in the left hand pane. The Joining Curve and Slip Lane Island page is displayed.

Joining Curves

The Inner Kerb Offset is the gap between the edge of the carriageway and the island.

The Outer Kerb Offset is the gap between the edge of the carriageway and the outside of the slip lane.

The Calculation Method determines how to create the inner curve of the slip lane:

• Fixed Arcs with Tangential Lines creates the curve using an arc, then tangent, then arc, then tangent then arc.
• Single Fixed Arc creates the curve using a single arc.

The Entry Radius is available when Fixed Arcs with Tangential Lines is selected and is the radius of the first arc.

The Middle Radius is the radius of the middle arc.

The Exit Radius is available when Fixed Arcs with Tangential Lines is selected and is the radius of the third arc.

Slip Lane Island

Select Island to set the properties of the slip lane island.

The Entry Island Radius is the radius of the end of island at the entry of the slip lane.

The Exit Island Radius is the radius of the end of island at the exit of the slip lane.

The Entry Island Width is the width of the island parallel to the Deceleration Region Length.

The Exit Island Width is the width of the island parallel to the Acceleration Region Length.

The Main Island Width is available when Fixed Arcs with Tangential Lines is selected for the Calculation Method and is the width of the island between the slip lane and the roundabout.