NAFE newsletters and articles

Forensic Engineering Analysis of Traffic Signal Timing and Speeds Prior to Collision by Rule-Based Triage of Indirect Video

Article Author:  Daniel P. Couture, PEng (NAFE 951M)

Volume: 34
Volume #: 1
Month: June
Year: 2017

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In most civil litigation cases pertaining to vehicle collisions, the courts attempt to assess and decide the proportion of shared liability of the drivers based on physical evidence as well as testimony of witnesses and perhaps experts. In North America’s modern electronic-flooded society, an immense quantity of video coverage has become available from sources such as cell phones, security cameras, eyes-in-the sky traffic helicopters, dashboard cameras, and even personal drones. However, rarely is the camera focused directly on the area of interest. Security cameras may be pointed toward the back door of a property yet still have visual coverage of a nearby street. When faced with a case having multiple conflicting eyewitness accounts, it was pondered whether some of this indirect collateral imagery could be converted into useful knowledge — without access to expensive supercomputer-based image analysis. The author considered whether there were any rules of inclusion or exclusion that may be used in the triage of video footage to assist with determining a timeline of an event. This paper will attempt to provide some guidelines to the formation of an adaptable rule set, as a foundation for conducting the triage process, with reference to published and validated data. It will then go over a case where the methodology was applied.


Tractor/trailer, vehicle, video, traffic signals, rule-based triage, stimulus, rural, second vehicle departure times, stopping probability

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