Roundabout Standard Editor: Arm Geometry: Slip Lane Curve

Expand Arm Geometry, click on the Slip Lane, then click on the Slip Lane Curve tab.

Joining Curve

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 Entry Radius is the radius of the first arc.

The Middle Radius is the radius of the middle arc.

The Exit Radius is the radius of the third arc.

Slip Lane Island

Select Island to set the standards 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.

In all cases the Max and Min values represent the limiting values from the adopted design standard and the Default value will be used when the roundabout is first placed. A default value MUST be provided but Max and Min may be blank if there is no limiting value.