Summit curves are required to be introduced at the situations where
A. a positive grade meets a negative grade
B. a positive grade meets another milder positive grade
C. a negative grade meets a steeper negative grade
D. all of the above
Answer:D
Summit curves are required to be introduced at the situations where
A. a positive grade meets a negative grade B. a positive grade meets another milder positive grade C. a negative grade meets a steeper negative grade D. all of the above