3.25 An overpass is being built over the PVI of an existing equal-tangent sag curve. The sag curve has a 70-mi/h design speed and G, = -5%, G, = +3%.Determine the minimum necessary clearance height of the overpass and the resultant elevation of the bottom of the overpass over the PVI. (Ignore the cross-sectional width of the overpass.)

Fig: 1