Roundabout Standard Editor: Arm Geometry: Levels & Grades

Expand Arm Geometry and click on the Levels & Grades tab.

The Grade at Blend Point (longitudinal) would normally be taken from the existing road surface. However, if the roundabout design requires that the existing surface levels at the blend point change, you may define a default gradient and limiting values which Roundabouts will use in its design checks.

The Vertical Transition Arc is a user defined arc of given radius where one end of which is tangential to the incoming road.

Crownlines

Note: Crowlinnes must be selected in the Roundel tab for these fields to be editable.

The Entry Side Transition Mode controls which method is used to define the entry crownlines.

• Custom
• Place Transition at Blend Point
• Place Transition at Deviation Point
• Place Transition at Splitter Deviation point

The Entry Side Cross Slope calculates the entry crossfall from the crownline of the road to the curb and is used to calculate the elevation of the outside curb, between the blend point and the change in transition.

The Entry Side Transition Distance sets the location for the entry transition.

Note: This field is only available when Custom is selected for the Entry Side Transition Mode.

The Deviation Offset From ICD sets the offset of the crossfall from the ICD location.

The Crown Line Offset at Entry sets an offset for the entry crown line as a percentage.

The Exit Side Transition Point controls which method is used to define the exit crownlines.

• Custom
• Place Transition at Blend Point
• Place Transition at Deviation Point
• Place Transition at Splitter Deviation point

The Exit Side Cross Slope calculates the exit crossfall from the crownline of the road to the curb and is used to calculate the elevation of the outside curb, between the blend point and the change in transition.

The Exit Side Transition Distance sets the location for the exit transition.

Note: This field is only available when Custom is selected for the Exit Side Transition Mode.

The Deviation Offset From ICD sets the offset of the crossfall from the ICD location.

Crown Line Offset at Exit sets an offset for the exit crown line as a percentage.

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.