A two-lane minor road intersects a divided four-lane major road at 900 forming a four-leg intersection. Traffic on the minor road is controlled by stop signs. Lanes on the major road are 12 ft wide and the median is 12 ft wide. The speed limits are 35 mph and 50 mph on the minor and major roads, respectively. If the design vehicle is a single-unit truck, determine the minimum sight distance required on the major road that will allow a stopped vehicle on the minor road to safely (a) turn left and (b) turn right. (totally 8 points)