Problem 4: A curve of radius 250 ft and e-0.08 is located at a section of an existing rural highway, which restricts the safe speed at this section of the highway to 50% of the design speed. This drastic reduction of safe speed resulted in a high accident rate at this section. To reduce the accident rate, a new alignment is to be designed with a horizontal curve. Determine the minimum radius of this curve if the safe speed should be increased to the design speed of the highway. Assume fs-0.17 for the existing curve, and the new curve is to be designed with e-0.08. (15 pts)