What section in the AASHTO Green Book addresses spiral curves?

• A. Sec. 3.3.8.1
• B. Sec. 3.3.8.3
• C. Sec. 3.2.5.4
• D. Sec. 3.4.2

Answer: (B)

The correct choice concerns spiral curves and pertains specifically to the part of the AASHTO Green Book that addresses the geometry of highway design. Section 3.3.8.3 in the AASHTO Green Book details the design of spiral curves, which are critical elements in roadway design for transitioning between straight sections and circular curves. These spiral transitions are important because they help vehicles navigate curves more comfortably and safely, providing a gradual change in alignment that reduces lateral acceleration on vehicles.

This section outlines the necessary parameters, characteristics, and design considerations that engineers need to account for when incorporating spiral curves into their designs. Understanding this aspect of design helps ensure both driver safety and the smooth operation of vehicles traversing the transition areas.

The other sections mentioned in the options do not focus specifically on spiral curves or the same level of detail related to their implementation in roadway design. Therefore, while they may cover related topics, they do not address the specific guidelines and considerations necessary for spiral curves in the same context.