Traffic Analysis Zones (TAZs) are geographical areas used in transportation planning. Let's analyze the statements:
(A) TAZs are generally not restricted by physical barriers such as rivers or mountains, but they are often defined by natural boundaries or land use patterns. However, this can vary depending on the study and area. Therefore, statement (A) is incorrect.
(B) Demographic characteristics such as population size and composition of a TAZ will indeed change as new residents move into the area. This is correct because TAZs reflect the changing nature of areas as population dynamics change. Therefore, statement (B) is correct.
(C) A cordon line helps to define the boundaries of the study area within which the TAZs are located, which is a standard method used in transportation planning. This makes statement (C) correct.
(D) TAZs can include multiple wards depending on the area’s size and population distribution. Therefore, statement (D) is incorrect.
Conclusion: The correct statements are (B) and (C).