This page shows 3 ways to display a single contour - by using the Tree View control you can display the information in different ways
These triangles are solved to generate the contour lines and may also be used for Volume calculations and Cut and Fill calcualtions

1 foot interval contour lines generated by using points shot of the original job area.     Pictures

1 foot interval Contour lines.  Red is high, Violet is low. Black lines are road edge, Hatched gray is box culvert

Same place with 2 ft contours. Two sets of contour lines are shown. Original in green and Proposed in blue