Intangible reference points should be marked on the roadway with which of the following?

Intangible reference points are crucial in a traffic crash investigation because they help investigators identify specific locations and provide a clear understanding of the crash scene. Using paint or chalk for marking these points is particularly effective because it offers a permanent and visible indication on the roadway that can withstand environmental conditions until the investigation is complete.

Paint or chalk allows for precise markings that can delineate lanes, vehicle paths, or other vital data that may be relevant to the investigation. The use of these substances also ensures that the markings are clear and legible for anyone reviewing the scene later, including other investigators, attorneys, or insurance adjusters.

In contrast, materials like plastic cones, flags, or markers serve different purposes, often being temporary and movable. While they can help with directing traffic or providing warnings, they do not offer the permanence or clarity needed for marking intangible reference points in an investigative context. Sand or soil, while they may be useful in certain scenarios, do not provide a reliable or visible way to mark critical data on roadways. Therefore, paint or chalk is the most suitable choice for marking intangible reference points during traffic crash investigations.