FE Civil Engineering Exam Prep

Answer: C - The passing sight distance for a section of 60 mph 2-lane rural highway with a 1,740-foot vertical sag curve where a bridge passes over at 16.8 feet is 2,273 feet.

Solution: Use sag vertical curve length at undercrossing equation (US Customary units)

S = L/2 + 400(C-5.75)/A

Where, L = 1740 feet

C = 16.8

A = 3.15

S = 1740/2 + 400(16.8-5.75)/3.15

= 2,273 feet