Which of the following could serve as a fixed reference point in a traffic crash investigation?

A fixed reference point in a traffic crash investigation is an immovable object that can be used to help establish the exact location of the accident. In this context, building corners are particularly useful because they provide defined, permanent, and easily identifiable landmarks that can be relied upon in future investigations or when documenting the scene.

Building corners offer a stable visual reference that remains unchanged over time, making it easier to create diagrams, analyze vehicle paths, and assess the dynamics of the crash. This assists investigators in accurately reconstructing the events leading up to and following the incident.

While the other options like sidewalks, traffic lights, and parking signs can provide helpful context and information about the crash scene, they may not always serve as reliable fixed references. For example, sidewalks may have variable entrances or be modified, traffic lights can be changed or relocated, and parking signs could be obstructed or removed. In contrast, building corners maintain their positions and can serve as steadfast markers, making them ideal for establishing a fixed point in crash investigations.