Citation

Brach RM. Collision 2011; 6(2): 78-86.

Copyright

(Copyright © 2011, Collision Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Data from event data recorders (EDRs) can be a useful supplement to traditional information used in accident reconstruction. In this paper, two example crash reconstructions are presented to illustrate how EDR data can be combined with other quantitative physical evidence. The cause of underreporting of speed values in EDR data is examined and a method to correct the speeds for heavy braking is presented. The author also analyzes EDR speed versus time data to estimate vehicle acceleration and position. The first example presented in the paper is a vehicle-pedestrian collision. In this example, the vehicle EDR data includes precrash speeds. This example demonstrates how knowledge of wheel slip can be used to correct underreported EDR vehicle speeds during braking. The second example is a reconstruction of a head-on crash of two vehicles. In this example, EDR data include both precrash speeds and delta-V values. A single comprehensive reconstruction of the initial vehicle speeds using the least squares method is conducted for this example, which combines the EDR data with a crush energy analysis. The reconstruction is formulated so that the results satisfy the principles of impulse and momentum. Both examples show that using appropriate validated mathematical models and software allows for accurate accident reconstruction using data from several sources, including EDRs.