Selected Cul-de-Sac Properties (Roundabout)

Rebuild method:

• Auto is the default setting that allows the intersection and corresponding surface to rebuild automatically after each change that affects it.
• Show empty - Select this to hide the surface in graphic views while you make edits. The surface cannot be automatically or manually rebuilt in this state.
• By user - Select this to suspend the process of rebuilding the intersection and surface until you select Rebuild Intersection.
• Parent corridor for the masses - When you calculate material volumes for a corridor, it will include the volumes for the connected cul-de-sac if you select the associated corridor here.

Minimize leg - As a standard definition, the road leg is minimized automatically (Yes). This option computes the shortest necessary length to the current leg. The minimized length will change depending on the other properties given to this leg.

If No is selected, another property is shown:

• Length of leg - This defines the total length of the leg that will be computed. The maximum length is the total length of current leg. The minimum length will depend on combinations of other properties, but cannot be shorter than the automatically minimized length of the leg.

Vertical adjustment method - Select a method for vertical adjustment of the road leg alignment:

• Select None if there is no vertical adjustment needed for the current leg.
• Select Tangent curve if the vertical alignment to the leg is making a tangential connection to the main road lane. If it is T- or X-intersection, it is to the primary road lane and is tangent to the slope of the main road. If it is a roundabout, it will tangent to the roundabout lane at the specific location where the tangent is.
• Select Linear if the vertical alignment will change linearly from the main road edge and the distance of the vertical adjustment length outbound along the leg.
• Select Line if the vertical alignment will be given a vertical straight line from the main road edge and the distance of the Vertical adjustment length outbound along the leg.
• Select Flat curve if the vertical alignment to the leg is starting with grade = 0 from the connection to the main road lane with the distance of the Vertical adjustment length outbound along the leg.

Vertical adjustment length - This shows the distance from the connection to the main road lane outbound along the leg.

Note: For more on roundabout tilt properties, see Intersection Properties.

Tilting - Automatic is the default, which means that the roundabout outer radius is tilted according to the legs of the intersection. If there are 3 legs, the tilting will be exactly matching to the elevation of the 3 legs. If there are more than 3 legs, the match will be optimized (least square best match). Then the inner radius of the roundabout will be "back calculated", meaning that the vertical alignment will be found by the slope of the roundabout lane. In this way, the slope of the lane will be correct if it is computed by difference of elevation between inner and outer radius of the roundabout (perpendicular to inner radius alignment).

• No tilt - Select this to prevent the roundabout's outer radius from being tilted. This means that the vertical alignment will be defined as a horizontal line segment with an elevation equal to the elevation of the intersect point. The inner radius vertical alignment will be computed the same way, as if tilted.
• User-defined - Select this to activate vertical adjustment functionality for the roundabout. The tilt can now be defined by a slope and tilt direction that you specify in the boxes below. The delta elevation for each leg is shown below.

Tilting

• Automatic tilt outer circle is the default, which means that the roundabout outer radius is tilted according to the legs of the intersection. If there are 3 legs, the tilting will be exactly matching to the elevation of the 3 legs. If there are more than 3 legs, the match will be optimized (least square best match). Then the inner radius of the roundabout will be "back calculated", meaning that the vertical alignment will be found by the slope of the roundabout lane. In this way, the slope of the lane will be correct if it is computed by difference of elevation between inner and outer radius of the roundabout (perpendicular to inner radius alignment).
  Tries to fit the roundabuot's outer circle so that the vertical difference between it and the incoming alignments. is as small as possible. This uses the leg elevation at the location where the outer circle intersects.

  

• User-defined tilt outer circle - Select this to activate vertical adjustment functionality for the roundabout and specify the slope and direction of the outer circle. The tilt can now be defined by a slope and tilt direction that you specify in the boxes below. The delta elevation for each leg is shown below.

  

• No tilt outer circle z reference - Select this to prevent the roundabout's outer radius from being tilted. Select this to specify the tilt of the outer circle and have the inner circle computed automatically based on the slope value of the lane. The lane slope is used to compute the tilt of the outer circle. This means that the vertical alignment will be defined as a horizontal line segment with an elevation equal to the elevation of the intersect point. The inner radius vertical alignment will be computed the same way, as if tilted.

  

• Automatic tilt inner circle - This uses the leg elevation at the location where the inner circle intersects. Automatic tilt is using vertical alignment of roundabout legs to find the best fit.
• User-defined tilt inner circle - Select this to specify the tilt of the inner circle and have the outer circle computed automatically based on the slope value.
• No tilt inner circle z reference - Select this to keep the inner circle horizontal based on the top elevation of the outer circle.

• Automatic tilt all circles - Outer circle defines the 'plane' by finding the intersection points with Leg-alignments. This will be the tilting values: Slope and Direction. Inner circle / Inner shoulder is parallel with the plane defined by Outer circle. In addition, there also is a couple of properties for offsetting these two inner lines.

  - Vertical offset inner shoulder

  - Vertical offset inner circle

  These properties are used to lift up/down both these inner lines

• User-defined tilt all circles - Specify the tilt (slope and direction) of both the inner and outer circles manually, and optionally the vertical offset between inner and outer circle (see Vertical offset inner shoulder and Vertical offset inner circle below). Lane and inner shoulder slopes are calculated automatically.

Slope - This shows either the automatically calculated or user-defined slope of the entire roundabout.

Tilt direction - This shows the bearing of the high side of the tilt, which you can control if the tilt is user-defined. The zero (0) bearing is north, and bearings are measured clockwise.

Vertical offset inner shoulder - Specify this vertical delta between inner shoulder and inner circle when using the User-defined tilt all circles tilt method described above.

Vertical offset inner circle - Specify this vertical delta between inner shoulder and inner circle when using the User-defined tilt all circles tilt method described above.

Delta elevation, Leg < > - For a user-defined tilt, this shows the deviation between the automatically calculated tilt and the one you have specified.

Slope - This shows either the automatically calculated or user-defined slope of the entire roundabout.

Tilt direction - This shows the bearing of the high side of the tilt, which you can control if the tilt is user-defined. The zero (0) bearing is north, and bearings are measured clockwise.

Delta elevation, Leg < > - For a user-defined tilt, this shows the deviation between the automatically calculated tilt and the one you have specified.

Island type - Select either a circular or tear-drop shape for the center island of the roundabout. There are additional properties for the Drop shape.

Drop radius (not available for Circle islands) -

Outer relative length (not available for Circle islands) -

Inner relative length (not available for Circle islands) -

In/out vertical turning method - This shows the method used to compute the vertical connection between two legs. The vertical curve is limited to the horizontal length of the corresponding curvature.

There are two methods:

• Linear connection - This method draws a straight line between the start and end point of the curvature. The method generates a tangential break both in the beginning and end of the curvature.

  

• Curve connection - This method computes a double arc/parabolic curve between the start and end point of the curvature. The method generates a tangential continuous curve both in the beginning and end of the curvature.

  

In radius - This is the access radius that is used in the horizontal methods.

Incoming horizontal turning method - This is the access method used in the horizontal method.

Incoming vertical turning method - This is the access method used in the vertical method.

Out radius - This is the exit radius that is used in the horizontal methods.

< > lane width - This shows the distance between the inner circle (radius above) and outer circle. This value is constant all the way around the roundabout.

Lane slope - This shows the slope of roundabout lane. A negative value means that the lane slopes down in the outbound direction. This value is constant all the way around the roundabout.

Note: If your intersection connects to a corridor that defines lanes (using instructions tagged with the Lane edge code), the Lane width and Lane slope properties do not appear here; these properties are controlled by the parameters in the corridor template instructions. See Create Corridor Template Instructions for more information.

< > shoulder width - This shows the width of the road's shoulder (distance between the outer circle and outer shoulder edge).

< > shoulder slope - This shows the slope of the road's shoulder. A negative value means that the shoulder slopes down in the outbound direction.

Curb height - This shows the vertical distance from the flow line to the top of curb.

Selected Cul-de-Sac Properties (Turning Hammer)

Rebuild method - See description above.

Parent corridor for the masses - When you calculate material volumes for a corridor, it will include the volumes for the connected cul-de-sac if you select the associated corridor here.

Type of turning hammer - Select Center, Left, Right, or X to mirror the real-world or design layout.

vertical turning method - This shows the method used to compute the vertical connection between two legs. The vertical curve is limited to the horizontal length of the corresponding curvature.

There are two methods:

• Linear connection - This method draws a straight line between the start and end point of the curvature. The method generates a tangential break both in the beginning and end of the curvature.
• Curve connection - This method computes a double arc/parabolic curve between the start and end point of the curvature. The method generates a tangential continuous curve both in the beginning and end of the curvature.

Minimize leg - As a standard definition, the road leg is minimized automatically (Yes). This option computes the shortest necessary length to the current leg. The minimized length will change depending on the other properties given to this leg.

If No is selected, another property is shown:

• Length of leg - This defines the total length of the leg that will be computed. The maximum length is the total length of current leg. The minimum length will depend on combinations of other properties, but cannot be shorter than the automatically minimized length of the leg.

< > lane width - This shows the distance between the inner circle (radius above) and outer circle. This value is constant all the way around the roundabout.

< > lane slope - This shows the slope of roundabout lane. A negative value means that the lane slopes down in outbound direction. This value is constant all the way around the roundabout.

< > shoulder width - This shows the width of the road's shoulder.

< > shoulder slope - This shows the slope of the road's shoulder. A negative value means that the shoulder slopes down from the centerline.

Note: If your intersection connects to a corridor that defines lanes (using instructions tagged with the Lane edge code), the Lane width and Lane slope properties do not appear here; these properties are controlled by the parameters in the corridor template instructions. See Create Corridor Template Instructions for more information.

Length - This shows the length of the calculated leg, starting from the end of the alignment.

< > lane width - See Main leg above.

< > lane slope - See Main leg above.

Radius -

Angle -

Shoulder -

Shoulder slope - See Main leg above.

See Virtual leg 1 above.

Selected Cul-de-Sac Properties (Turning Hammer)

Left/Right - Specify the side of the road on which to add the knoll (bulge, "beer belly").