OpenBridge Modeler

Calculate Superelevation

Used to compute the station and cross slopes of transitions.

You can access this tool from the following:

  • Ribbon: Corridors > Superelevation > Calculate split button

In this step, there are two options: rule-based and imported data. Generally, one method would be selected, however, you can use rule-based for part of the project and import other parts (although this would be confusing).

The rules-based tool uses a rules file to compute the station and cross slopes of transitions, while the import superelevation method uses a comma separate values (CSV) file containing the station and cross slopes, which were calculated by an exterior program (or manually). The inputs vary depending on the method used and the preferences within the rules file.

The result of this step is the augmentation of station/cross slopes of transitions to the lanes created in the previous step. It's easy to see the results if the fill is toggled on as the lanes change from solid yellow and green to a gradient coloring, based on cross slopes.


1. Select Calculate Superelevation.

2. Follow the heads-up prompts for SEP file.


User Action

Locate First Superelevation Section

Select the first section. In lieu of selecting each section individually, drag your cursor diagonally across all desired sections. Your diagonal defines a square wherein the entire section must be encompassed in order to be included.

Locate Next Superelevation Section or Reset to Complete

Continue selecting sections until all are highlighted, then reset to move to the next prompt.

Standards File Name

Select the SEP or SRL file containing the superelevation standards/parameters. Use <ALT> <DOWN> to open the File Manager to select directory/file. Data prompt to accept and move to the next prompt.

Note: The prompts below and their options may vary based on the options within the rules file.

e Selection

L Selection

The available e and length Selection fields are filled in according to the SEP file. Those combo boxes determine which table within the .sep file will be used for computation.

Design Speed

Design Speed is to be used either in the tables or equations for e and length computations.

Pivot Method

Rotation only

Transition ID

Linear or a variety of parabolic options, based on the settings in the SEP or SRL files. If the SEP file is set to parabolic, then the following options are supported:

Parabolic reverse curve - This symmetrical option utilizes the parabolic transition with no tangent and the length of each parabola is one-half the transition length.

Parabolic Reverse Nonsymmetrical Curve 1 - Lengths of the two parabolas are specified: Sag parabolic Length (L1) =45 and Crest Parabolic Length (L2) = 55. The Tangent Length = Transition Length - (L1+L2) as depicted below.

Parabolic Reverse Nonsymmetrical Curve 2 - Lengths of the two parabolas are specified: Sag parabolic Length (L1) =30 and Crest Parabolic Length (L2) = 40. The Tangent Length = Transition Length - (L1+L2) as depicted above.

The values of the parabolic lengths are set by configuration variables by default. To change the values, add the configuration variable and the desired values.

Number of Lanes

Used to determine when adjustment factors are applied.


Divided or undivided: determines which values to use for Distribute Over and % on Tangent options.

Ease Length

Not utilized in SEP files.

Add Constraints

Not supported in SEP files.

Open Editor

When calculations are complete and lanes updated, the superelevation editor is opened and populated with the new calculated lanes.