Abstract
Those of us who practice in the forensic area are aware that many litigated vehicle crashes occur during hours of darkness, when visual cues that alert drivers to hazards are either missing or compromised due to the characteristics of headlights. One particular type of crash of interest to forensic practitioners is a passenger vehicle driving beneath a trailer that is positioned across the roadway during a backing or pullout maneuver. In addition to the loss of certain visual cues, such crashes are frequently characterized by the presence of the tractor pulling the trailer being located in the oncoming travel lane. This may appear to the oncoming motorist to be a benign situation, i.e., a vehicle approaching in the adjacent travel lane. The headlights of the tractor not only provide a false cue to the oncoming motorist, they are also a source of disability glare. In this paper, we model the effects of disability glare during a typical crash scenario. Despite efforts to bias the analysis to minimize the effects of disability glare, it is clear that such glare may hide the presence of the trailer until the oncoming vehicle is relatively close to it, thus reducing the chance of the oncoming driver to avoid an underride collision.