Citation

Bartlett W. Accid. Reconstr. J. 2010; 20(1): 39-41.

Copyright

(Copyright © 2010, Accident Reconstruction Journal)

DOI

unavailable

PMID

unavailable

Abstract

This article reminds readers of the importance of the "old-fashioned" accident reconstruction techniques of coordinate method and triangulation. The coordinate, or Cartesian, method involves pulling a tape measure along a straight baseline and measuring perpendicular to that for each point of interest; this method works well for accident areas with straight roads. Triangulation is more useful for scenes with curves or more complicated geometry, or where there are obstacles in the roadway preventing easy access. The author walks readers through the triangulation of one complicated accident scene. The example case involves a 96-foot diameter traffic circle in Pepperell, Massachusetts where two roads come together at odd angles. The first step was to make a free-hand sketch of the scene, then decide on measurement points, label them on the sketch, and mark them with water-soluble paint on the roadway. The data is transferred to a CAD program and all the points are mapped. Overhead photographs can be used for comparison. The author concludes by reminding readers that there are a number of variations available on the theme of triangulation, but all of them depend on measuring complete triangles that tie together across the whole scene.