Which of the following is one of the two primary methods of measuring at a crash scene?

The correct choice is the Coordinate Method, as it is one of the primary techniques used to measure and document a crash scene accurately. This method involves establishing a coordinate system to map the locations of key evidence, vehicles, and other relevant points on the scene. By using a set of coordinates (X, Y), investigators can create a precise layout that enables a clear understanding of how the crash occurred and can be utilized in reports and for reconstruction purposes.

In contrast, the Linear Method, while effective, is typically considered less systematic and can lead to inaccuracies if not implemented correctly. Meanwhile, the Aggregation Method and the Proportional Method are not standard methods recognized for traffic crash scene measurements in the context of formal investigations. Focusing on the Coordinate Method allows for greater accuracy and clarity when documenting the specifics of a crash scene, which is vital for legal proceedings and insurance assessments.