The Horizontal Curves Panel allows dynamic modification of the currently
selected Horizontal IP or curve (visible in the Plan Window). It is activated by selecting the
Window - New Window - Horizontal Curves menu or by
clicking the
button on the Standard
toolbar. See also Horizontal Curves.
Advanced Mode includes spiral curves, more super-elevation control and design speed. This option is disabled in some products.
Open the Road Class Specifications Dialog by
clicking the
button on the Curves Panel. Unselect the Simple
Curves option and press OK. The Curve Panel will close and
then re-open in advanced mode. The the Road Class Specifications Dialog
is also available as a tab in the Template Table Dialog
box.
At the top of this window is a description line showing the curve number and stationing of the currently selected curve or IP if applicable.
This type of Window can be displayed as a docked panel or as a floating window. See Panel Windows, Common Features for more information.
Defines curvature. When you change Radius, the IP and Tangent Parameters update instantly. If the curve does not fit the available tangents, the Apply button will be disabled and a warning will be reported.
Allows you to change the super-elevation of the curve.
This is accomplished by changing the cross-fall of template legs that have the "apply super-elevation" property. Some templates may not respond to super-elevation if no such legs exist.
The Transition Length is both the super-elevation runoff length and the curve widening transition length. If you are not using Super-Elevation or Curve Widening, the Transition Length has no effect.
Super-elevation runoff is defined as the distance from zero cross-fall (flat) to full super-elevation to on the outside lane. If the normal cross section has a crown, then an additional transition is required from crown to zero cross-fall (the start of Super-elevation runoff ); this transition is called the Tangent Runout and it occurs outside of the transition length.

The Tangent Runout length is calculated so that the rate of change of cross-fall is the same as in the Super-elevation Runoff. For example if the full super-elevation is 6% and the Transition Length (= Super-elevation Runoff) is 60m, then the rate of change of cross-fall is 10m/%. If the crown slope is 2%, then the Tangent Runout will be 20m. In this case, the total transition length is 80m, 20m more than the value specified in the Transition Length field.
The software will not allow you to design adjacent curves that have curved segments overlapping. However, it is reasonable to design curves with overlapping transition zones.
Allows you to change where the transition starts; it is the fraction of the Transition Length (above) that occurs outside the actual curve.
For example if the Transition Fraction is set to 0.75 and the Transition Length is 100m, the transition will start 75m before the BC point and be completed 25m after the BC point. Similarly, the exit transition will start 25m before the EC and end 75m after the EC.
The curve widening values are added to the normal lane widths in the curve region. Inside and outside depend on the direction of the curve. For a right hand curve the inside is on the right hand side of center line while the outside is on the left. For a left hand curve, inside is left and outside is right.
Widening is accomplished by lengthening template legs that have the "apply curve widening" property. Some templates may not respond to curve widening if no such legs exist.
If an Auto box is checked, the associated Widening field is
disabled and the value is extracted from a table. The
button pops up the Automatic Curve Widening Options dialog box, allowing you to
read in a new Curve Widening Table and/or change the way the table is
interpreted.
Note that If the Curve Widening Table is not defined, checking an Auto box will automatically pop up the Automatic Curve Widening Options dialog box.
These radio buttons define whether a curve exists.
Select Circle (the only type of curve supported in Simple mode) to define a curve and to enable the other curve parameter controls (above).
Select No Curve to remove a curve and to disable the controls.
Saves changes to the above values, and updates alignment and all windows to show the result.
If the Apply button is not available, it means one of two things:
1 The curve has not been changed from the one already
applied.
2 The curve can't be applied to the current alignment. In this
event the reason will be reported left of the Apply button; for example
"Curve does not fit tangents".
Moves the current selection to the previous or next IP or curve along the horizontal alignment. Any changes made to the current curve or IP are lost unless you have Applied them.
Note that when a curve is selected, the Current Point displayed in the other windows is the EC (End Curve) point.
This button pops up the Road Class Specifications Dialog.
The first button saves the parameters for the current curve as the new Default Curve.
The second button retrieves the Default Curve parameters. Once your Default Curve is defined, creating a new curve requires two button clicks: Get Default Curve and Apply.
Default Curves (Vertical and Horizontal) are saved with your template table; they are saved with your document and can also be saved externally in a TPL file. Open and update your standard template table files (Normal.tpl and possibly others) to make default curves available in new projects.
Opens the help browser with this page displayed.
Shows the arc length of the current curve (0.0 if No Curve).
Shows the delta angle (change in azimuth) of the current IP/curve.
If a curve is defined, these fields display the BC (Begin Curve), EC (End Curve) and IP (Intersection Point) coordinates of the currently selected curve.
If a curve is not defined, they show the coordinates of the previous, current and next IPs.
The incoming and outgoing azimuths are also displayed.
Allows you to Add a Horizontal IP. This button is disabled if you haven't Applied changes made to the current curve/IP.
Allows you to Modify a Horizontal IP. After you exit the Modify Horizontal IP dialog box, you must Apply your changes before they take effect.
Deletes the current IP (and curve if defined).