Extracted text: A spiral is to be introduced to a 4-lane highway with a 2° 30' horizontal curve, maximum superelevation rate of 6%, and a design speed of 70 mph. The curve has a central angle (A.) of 25°. If the TS station is 15+00, type your answers to the following items without showing equations or calculations. 1. Radius of curve 2. Length of curve 3. Length of spiral 4. SC station 5. CS station 6. ST station