Background FMVSS 108 specifies requirements for original and replacement lamps, reflective devices, and associated equipment. The goal is to reduce traffic crashes and related deaths and injuries by providing adequate roadway illumination. The agency wants to enhance the conspicuity of motor vehicles so that their presence is perceived and their signals understood, both in daylight, darkness, or other conditions of reduced visibility. However, with the introduction of high intensity discharge headlamps (HIDs) and look-alike halogen bulbs, the high-mounted headlamps on the popular LTVs, and the upswing in auxiliary lamp use, consumers have registered complaints about glare issues. Glare, whether at levels that are annoying or disabling, increases the stress for drivers in the more dangerous nighttime environment that can result in a greater safety risk.

ObjectiveQuantify the range of glare problems from lamps in today's passenger vehicles. Determine if the effects of glare from HIDs, high-mounted headlamps, and auxiliary lamps increases crashes, injuries, and fatalities.

Proposed Approach Examine and analyze crash data from the FARS, NASS, and State data files to identify crash cases impacted by glare. Measure the headlight aim and the headlamp mounting height on LTVs. Develop a laboratory test setup to assess the degree of glare from various passenger vehicles (based on quantitative measurement and/or judgment by volunteers). Determine if specific LTV make-models have more issues/complaints with glare. Determine if there is a difference in glare from direct view (headlamps shining directly into the eyes of oncoming drivers) or from indirect view (headlamps shining directly into the mirrors of preceding passenger vehicles). Determine which type of glare produces more stress for drivers in the nighttime environment. Determine which type of glare increases the possibility of crashes. Determine if specific age groups are more affected by glare. Review consumer complaints. The evaluation is likely to take 3 years, since it combines extensive data collection and statistical analyses.