Looming in Forensics: Misapplication,Correction and Extension

Abstract

In recent litigation Human Factors Experts have been misapplying the analysis of the looming threshold for offset motions. Looming (or image size expansion) analysis is appropriate for a rapid direct approach to an object (i.e., rear-end collisions) but is inappropriate for offset motions. Typically, looming threshold analysis is applied to nighttime driving when approaching a slow-moving or stopped vehicle presenting no visual cues other than rear tail lights. This paper lays out the foundation for looming, derives the accepted mathematical equation, and compares it to the rate of visual angle change, which is more applicable to offset motions. An appropriate offset looming threshold equation is derived. In addition, a special case of collision due to looming combined with lateral motion is addressed which has historical significance in open water vessel navigation.