Geometric Road Design
University of Nebraska Lincoln
Mid-American Transportation Center
Summer Institute Engineering Experience Day
Roadway Online Application for Design (ROAD)
MTO/CE/ITS Institute, University of Minnesota
We will create a continuous roadway from point C to point E. Our road should have a curve that passes through B.
Directions:
Open design file
( Go to: and import contour image)
Horizontal Road Design: (Bird’s Eye View)
2. Select the line tool and create a line segment from C to B.
3. Create a line segment from B to E.
4. To create the curve we need to add a circle that touches both line segments.
Tangent: ______.
5. Make lines tangent to circle. Use the arrow button. Select two line segments and the circle. Select the button with a curve and line segment with arrows that point towards each other. Your lines are now tangent to the circle.
6. We need to mark several important spots on our road. We need to mark the beginning and endpoints, tangent points, and any place where our road intersects a contour line. Use the “H” button to mark your important points and enter the elevation at those points. Make sure you ENTER LANDMARKS IN ORDER.
7. We have now marked the path of our road. To see our road select View then “Road Only”
8. Save your file.
Vertical Curve Design: Making our road smooth during changes in elevation
1. Change to Cross Sectional View of our road by selecting the last button in the tool bar
Cross Sectional View:______.
2. We need to change smooth out the hills and valleys. We will use the digging man to draw lines that change the grade.
Grade: ______
Cut: ______
Fill:______
3. Once you have new black lines select the third button to create curves with parabolas. If a warning box pops up, you will have to select “edit” then “clear design” and begin again. If you receive a warning box, wait and we will create our design together.
4. Save your file.
Vertical Design Questions:
1. What is the highest elevation of the original curve? What is the distance on the road at this point? Can you write these qualities as an ordered pair?
2. What is the highest elevation of our new road? What is the distance on the road at this point? Can you write these qualities as an ordered pair?
3. What is the lowest elevation of the original curve? What is the distance on the road at this point? Can you write these qualities as an ordered pair?
4. What is the highest elevation of our new road? What is the distance on the road at this point? Can you write these qualities as an ordered pair?
Fill/Cut Report:
This will show us how much we need to build the earth up or “cut” it down in order to create our smooth vertical road design.
Fill/Cut Questions:
1. At what distance in the road is the difference between the road and original landscape the greatest? What type of earthwork is this? Can you write it as an ordered pair?
2. What is the deepest fill? At what distance on the road does this fill occur? Can you write it as an ordered pair?
3. At what distances is the road at the same elevation as the original landscape?
4. How long is our road?
Roadway Design Report:
Select the second last button to create the report.
1. Do you see any warnings? Why is this a problem?
2. What is the total amount of cubic yards that will need to be filled to create our road?
3. What is the total amount of cubic yards of earth that needs to be cut?
4. Do we need more “earth” or do we have too much “earth”?
5. If dump trucks carry 8 cubic yards, how many dump trucks of dirt do we need to transport the dirt?