Which of the following unit descriptions is NOT allowed on the CR-3?

The unit descriptions within the CR-3 form, which is utilized for documenting traffic accidents, have specific criteria that dictate what can be included. The correct answer highlights that not all types of vehicles can be described on the CR-3.

In this case, the inclusion of both motorcycle and bicycle in the list suggests that these vehicles are commonly documented; however, a CR-3 form typically focuses on motor vehicle accidents involving motorized vehicles primarily. The fact that "All the above" is marked as the answer implies that the question is addressing the appropriateness of containing non-motorized vehicles like bicycles in the context of the form.

Thus, the accurate interpretation is that the CR-3 form does not permit unit descriptions for all mentioned vehicles due to the emphasis on motorized traffic incidents. This means that while motorcycles can be included because they are motorized, bicycles are generally excluded from the CR-3 documentation, leading to the conclusion that option C, which encompasses all the choices, is the correct answer. This effectively clarifies that only specific motorized vehicles are allowed for documentation on the CR-3 form.