Field Measurements & Scale Diagrams in Traffic Crash Investigation & Reconstruction
One of the most important aspects of the entire traffic accident investigation process is the taking and recording of accurate and adequate measurements during the on-scene investigation. Properly made and recorded measurements serve to:
- Refresh an investigator's memory of an investigation.
- Enable an investigator to testify, perhaps at a much later time, with accuracy and confidence regarding the positions and locations of items at an accident scene.
- Enable an investigator or someone else to prepare a scale diagram or map of a crash scene.
- Assist in reconstructing a crash scene.
- Assist in determining how and why a crash occurred.
Measurements are usually made on a field sketch, which is a rough draft made in a rapid, summary way, and which contains factual after-crash measurements taken at an accident scene. There are many things that must be included in a field sketch, yet there are many things that should not be included. For example, only that which is seen at the time the sketch is made should be included; but things that cannot be explained (such things can form a part of the investigator's notes) should not be included.
Coordinate, triangulation, and grid measuring methods are most often employed in preparing a sketch. In many cases, it is necessary to use congruent and similar triangles to measure the location of items in restricted areas, such as a vehicle in a river.
For detailed field sketch measurements procedures and scale diagrams preparation, see Traffic Accident Investigators' and Reconstructionists' Field Measurements and Scale Diagrams Manual (2nd ed.). Published by Charles C Thomas -2002.
For details on this and other relevant publications, visit the Books Page, including the following:
RIVERS, R.W.: Technical Traffic Accident Investigators' Handbook (2nd ed.). Published by Charles C Thomas - Publisher, 1997.
RIVERS, R.W.: Traffic Accident Investigators' Manual (2nd ed.). Published by Charles C Thomas - Publisher, 1995.
RIVERS, R.W.: Training and Reference Manual for Traffic Accident Investigation (2nd ed.). Published by the Institute of Police Technology and Management (IPTM), 1995.
RIVERS, R.W.: Seat Belt and Air Bag Systems Manual for Traffic Crash Investigation and Reconstruction. Published by the Institute of Police Technology and Management (IPTM), 2001.