The vertical curve passes over an existing underground waterline that runs perpendicular to the roadway at station 20+91.00. The top of the waterline is at elevation 407.50 feet. The minimum clearance between the roadway and the waterline must be 6 feet. The PVI is located at station 19+00.00 with elevation 420.50 feet. The design speed of the curve is 55 mph, g1 is +3%, and g2 is -3.0%. PRT= 2.5 sec, 0.35 = friction factor.
a. Calculate the minimum length of this curve.
b. Determine if the clearance between the vertical curve and the waterline is adequate.
c. If the clearance is not adequate in this type of case what modification to L would be required to increase the clearance? Discuss possible ramifications of making this modification.