Roundabout Properties: Arm: Splitter ETW Construction

Expand an arm and click Splitter ETW Construction in the left-hand pane. The Splitter ETW Construction page is displayed.

The Calculation Method sets how the side of the splitter is defined. Fields in the rest of the dialog box become available based on this selection.

• Single Arc: The side is based on the radius of a single arc.
• Line Arc: The side is based on a line, then an arc.
• Arc Tangent Arc: The side is based on a arc, then a tangent line, then another arc.

The Entry Arcs Target defines the object that the edges of the splitter island line up with within the roundabout.

• Central Island
• Apron
• Inner Edge Of Travel Way
• Inside of Outer Lane

The Make Adjusted Alignments Straight in Construction Triangle Region check box is available when Line Arc or Arc Tangent Arc is selected as a Calculation Method.

The Construction Triangle Width sets the width of the splitter triangle.

The Construction Triangle Length sets the length of the splitter triangle.

The Construction Triangle Start Offset sets the offset of the start of the triangle from the centre line of the incoming arm.

The Construction Triangle Centre Offset sets the offset of the centre of the island from the centre line of the incoming arm.

The Entry Radius Sets the entry section of the arm's radius along the splitter.

The Entry Taper Radius sets the initial entry taper radius along the splitter.

The Exit Radius sets the exit section of the arm's radius along the splitter.

The Exit Taper Radius sets the diverging taper radius along the splitter.

Expressed As Ratios of the Inscribed Circle Radius

The Ratio values are calculated as the radius of the Roundel ETW * Ratio = Length.

Maintain the ratios when changing the inscribed radius

• Unchecked: Changes to the Distance values update the equivalent Ratio value
• Checked: Changes to the Ratio values update the equivalent Distance value

The Construction Triangle Width Ratio sets the width of the splitter triangle as a ratio.

The Construction Triangle Length Ratio sets the length of the splitter Triangle as a ratio.

The Construction Triangle Start Offset Ratio sets the offset of the start of the triangle from the centre line of the incoming arm as a ratio.

The Construction Triangle Centre Offset Ratio Sets the offset of the centre of the island from the center line of the incoming arm as a ratio.

The Entry Radius Ratio sets the entry section of the arm 's radius along the splitter as a ratio.

The Entry Taper Radius Ratio sets the initial merging taper radius along the splitter as a ratio.

The Exit Radius Ratio sets the exit section of the arm's radius along the splitter as a ratio.

The Exit Taper Radius Ratio sets the diverging taper radius along the splitter as a ratio.