Viewing the corridor surface slopes allows you to evaluate the finish design surface of the corridor surface for minimum and maximum slopes.

Perform a slope analysis of the finish surface of the corridor model to locate flat and steep slopes.

1. In Tool Space dialog, Prospector tab:
   • Expand Surfaces
   • Right-click ‘Finish Surface’, select Surface Properties
2. In Surface Properties dialog box, Analysis tab:
   • For Analysis Type, select Slopes
     Note: The criteria for the analysis are stored in this surface’s properties.
   • Check Preview.
     The preview summarizes the total area for each range.
   • Notice the analysis queries and renders surface triangles differently according to the slope range they fall within. A red shape indicates a surface triangle with a slope less than 0.5% and a purple triangle indicates a surface triangle with a slope greater than a 2:1 (50%).
     
3. In Surface Properties dialog box, Information tab:
   • For Surface Style, select Slope Analysis
   • Click OK
     
4. In the drawing area:
   • Notice the red area indicates a pavement slope less than the minimum 0.5%. This situation generally occurs when a flatter longitudinal grade in the design profile and the level crown (sometimes referred to as zero high side) station in the superelevation transition coincide. This small area is acceptable.
     
   • Notice the purple area indicates a cut or fill slope greater than the maximum 2:1. This situation was caused by the steepening of cut slopes to daylight inside or on the existing right-of-way. This may require special erosion control and soil stabilization consideration in areas where the slope exceeds the maximum 2:1.