Parameters related to a rotary intersection:
1. Width of the weaving section: The width of the weaving section refers to the distance between the inner edges of the two carriageways at the rotary intersection where vehicles merge or diverge. It is an important parameter as it determines the space available for vehicles to change lanes and perform weaving maneuvers.

2. Length of the weaving section: The length of the weaving section is the distance along the carriageway where vehicles merge or diverge within the rotary intersection. It is essential to provide sufficient length to allow vehicles to complete weaving maneuvers safely without causing disruptions or conflicts with other vehicles.

3. Proportion of weaving traffic: The proportion of weaving traffic refers to the percentage of vehicles entering or exiting the rotary intersection that need to perform weaving maneuvers. This parameter helps in understanding the demand for weaving movements and aids in determining the capacity of the intersection.

4. Weaving angle: The weaving angle is the angle between the two carriageways at the point where vehicles merge or diverge within the rotary intersection. It influences the complexity and safety of weaving maneuvers. A larger weaving angle may require vehicles to make sharper turns, increasing the difficulty of merging or diverging.

5. Width of the carriageway at entry: The width of the carriageway at entry is the width of the road where vehicles enter the rotary intersection. It plays a crucial role in determining the capacity and efficiency of the intersection, as wider carriageways allow for smoother merging and better traffic flow.

Capacity expression:
The capacity of a rotary intersection is generally expressed in terms of the parameters mentioned above. The correct answer, option D, includes all the relevant parameters (1, 2, 3, and 5) that contribute to determining the capacity of the intersection. Each parameter contributes to the overall efficiency and functionality of the intersection, and considering all of them is essential for accurate capacity estimation.

By considering the width and length of the weaving section, the proportion of weaving traffic, and the width of the carriageway at entry, engineers and planners can analyze the operational characteristics of the intersection and estimate its capacity. This information is crucial for designing and managing the intersection effectively, ensuring safe and smooth traffic flow while minimizing congestion and delays.