SUR 4201 Route Geometrics SR25 CASE
Situation: State Road 25 has specified Horizontal, Vertical and Cross Section geometry
as follows:
A. Horizontal Specifications:
1. The first baseline tangent is to start at station 10+00.00 and at Cartesian coordinates of
5000 ft North and 5000 ft East, and proceeds 1000 feet at an azimuth of 85 degrees to the
first point of intersection.
2. The second route tangent deflects from the first 42 degrees to the left and has a total
tangent length of 2000 feet to a second point of intersection.
3. The third tangent deflects 32 degrees right and measures 1000 feet in total length to
the End of Project point where the new baseline meets an existing road centerline of
azimuth 75 degrees.
4. Circular curves are to be placed at each point of intersection. The radius of Curve 1
and Curve 2 are to be the same and equal to 1000 ft.
Vertical Specifications:
5. The baseline is to have elevation 58.00 feet at the project's beginning point, station
10+00. The first vertical tangent's percent grade must be - 2.00% and run to a PVI at
station 25.
6. Run the second vertical tangent at +2.50% to a PVI at station 35.
7. The final vertical tangent joins the last PVI with the project's end point which must be
at elevation 53.00 feet.
8. Choose lengths of the two required vertical curves to have a K value of 200 feet/%.
Cross Section Specifications:
9. The baseline is to be the centerline between two traffic lanes of 12 ft in width each,
crowned at 2%. A 3 ft shoulder is to be provided on each side, sloped at 5% to make
sure water drains well. Use 3:1 side slopes in cut or fill to original ground. The
pavement consists of 6 inches of asphalt on top of 12 inches lime rock base. You are to
exclude the area of pavement and rock from your earthwork calculations. Construct cross
sections at each 500 ft station (10, 15, etc to End Project) and use these to determine
earthwork volumes. When the project "transitions" between cut and fill, estimate the
intermediate station of transition and use this for volume calculations.
Existing Ground Measurements:
10. At each station point the land is exactly the same elevation for a considerable
distance left and right of the baseline. The existing ground along the baseline has the
following elevations:
10+00, 52.00 ft 30+00, 44.00 End Project, 52.00
15+00, 50.00 35+00, 46.00
20+00, 39.00 40+00, 58.00
25+00, 34.00 45+00, 50.00
(In volume calculations, also use end areas of zero area at your estimated transition
stations between cut/fill stations).
