Were Lights Automatically Illuminated?


R. Scott King, BSME ::::

Case Synopsis: The operator of a small school bus made a left turn into the path of an oncoming early model Ford Explorer.  Afterward, the bus operator reported that dense fog prevented him from seeing the oncoming Ford before committing to the turn.  The driver also indicated that the Ford’s lights were not activated, and thus contributed to his inability to see the vehicle. 

At deposition, the Ford operator testified that his lights were illuminated even though photographs taken at the scene clearly showed the headlamp switch was off.  He also provided detailed testimony regarding the operation of his vehicle’s lighting system.  In particular, he testified that his vehicle was equipped with daytime running lamps (DRL) that illuminated automatically whenever the vehicle was in operation.  He also testified that his vehicle was equipped with a twilight sensing system that switched the headlights on and off regardless of the headlamp switch position and further, that certain aftermarket lights also illuminated automatically.

Engineering Evaluation: Because of the conflicting testimony, an engineering evaluation was initiated. That evaluation began with technical research of the standard and optional content of the incident vehicle.  That research revealed that the DRL system was offered as optional equipment but that the twilight sensing system was not available, either as standard or optional equipment.  An analysis of the wiring schematics showed where the various components of the DRL system would be located if the vehicle was so equipped.  The evaluation concluded with a non-destructive vehicle examination.  This inspection revealed that, consistent with the preliminary research, the vehicle was not equipped with a twilight sensing system.  The inspection also revealed that, despite the owner’s testimony, the vehicle was not equipped with DRL.  Further testing revealed that the headlights and aftermarket lighting was functional, but only when the headlamp switch was activated.

Conclusion: The evaluation provided the basis for the opinion that unless the operator activated the headlight switch, none of the vehicle’s exterior lamps would have been illuminated at the time of the incident and helped facilitate a settlement for a fraction of plaintiff’s initial demand.

Categories: Case Studies


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