What does R2 in median design represent?

• A. The total width of a roadway
• B. The length of a turn bay
• C. The radius of a circular median opening
• D. The setback distance between lanes

Answer: (C)

In median design, R2 denotes the radius of a circular median opening. This measurement is crucial for determining how vehicles can safely navigate through or around a median. A well-designed median with an appropriate radius allows for smoother transitions and enhances safety by reducing the likelihood of overshooting the median or experiencing vehicle instability. The circular opening needs to be sufficient to accommodate turning movements without undue strain on vehicle systems, thus aiding in traffic flow and providing safe access to cross streets or pedestrian pathways.

The other options, although relevant in various contexts of roadway design, do not specifically address the function of R2 in median geometry.