What section and equation in the AASHTO Green Book discuss superelevation?

• A. Sec. 3.3.2, Eq. 3-8
• B. Sec. 3.3.1, Eq. 3-6
• C. Sec. 3.3.2, Eq. 3-6
• D. Sec. 3.3.3, Eq. 3-9

Answer: (C)

The correct section and equation related to superelevation in the AASHTO Green Book is found in Section 3.3.2, Equation 3-6. This section specifically addresses the design considerations for superelevation, which is the banking of the roadway at a curve to counteract the effects of centrifugal force on vehicles.

The equation itself provides the mathematical framework for determining the appropriate rate of superelevation based on various parameters including design speed and curve radius. Using this equation ensures that the road is safe and comfortable for vehicles negotiating curves, enhancing both the operational performance and safety of the roadway.

Understanding the proper implementation of superelevation is crucial, as it helps maintain vehicle stability, allows for higher speeds on curves without compromising safety, and contributes to more effective drainage of water from the pavement surface. This knowledge is essential for civil engineers involved in transportation design.