Effect of Oxidation on Headlight Illumination

This incident involved a pedestrian walking along an unlit roadway during the night hours. The pedestrian was wearing gray-colored clothing and was walking in the direction of traffic. Contact occurred between the right front aspect of the striking vehicle and the pedestrian. ARCCA’s accident reconstruction team was tasked with investigating the striking vehicle’s headlamps.
 

Steps Taken:

  • The striking vehicle was inspected, and the condition of the headlight assemblies was documented.
  • The vehicle was taken to ARCCA’s test facility to further investigate the vehicle’s headlight illumination.
  • Once at ARCCA’s facilities, the aim of each headlight assembly was benchmarked against SAE and FMVSS standards.
  • To quantify the light output of the existing headlight assemblies, the beam pattern was mapped utilizing advanced light metering equipment.
  • The existing headlight assemblies were then replaced with exemplar assemblies in new condition.
  • The new headlight assemblies were aimed in accordance with SAE and FMVSS standards and the intensity of the beam pattern mapped.

Final Findings:

  • The existing headlight assemblies were found to have significant levels of oxidation and hazing.
  • When comparing the existing headlight assemblies to the new assemblies, the light intensity at 24 inches above ground was as much as 6 times greater at various locations for the new headlights.
  • The 10 lux threshold was extended by nearly 100 feet with the new headlight assemblies.
  • The subject headlights affected the driver’s ability to recognize the pedestrian walking along the roadway.

Headlight mapping of existing assemblies.

Headlight mapping of new assemblies.