( A horizontal curve is designed for a two-lane road in a level terrain. The following data are known: Central angle (A): 50 degrees Design speed of 80 km/h Side friction factor = 0.12 Superelevation = 0.08 Lane width= 3.60 m Normal crown slope = 2% Determine the minimum radius of the curve, the minimum and maximum length of spiral curve and the length of the circular curve. Draw 3 neat and well labelled sketches of the roadway cross sections overlaying the normal crown on the fully superelevated section; for the following 3 scenarios: a) Rotation about the road centreline b) Rotation about the inside edge of pavement c) Rotation about the outside edge of pavement Discuss the impact of each method of rotation on drainage and amount of earthwork.