This study examines the ongoing challenge of balancing sufficient forward illumination for vehicle operation with the need to limit glare experienced by other road users. This analysis specifically focuses on the portion of a headlight's beam pattern intensity distribution located above the horizontal plane, which is particularly relevant for lighting overhead signs and the upper portions of vulnerable road users but is also a potential contributor to glare. In particular, the study investigates how the adoption of LED headlamp technology has influenced upward-directed lighting relative to historical halogen beam intensity distributions.
Two different comparative analyses were performed within this study. The first analysis was the calculation of intensity on targets positioned at multiple locations relative to the headlamps considering vehicle conditions. The second analysis was performed as at selected discrete points referenced directly to the headlamp and independent of vehicle height.
The results of the study show that the changes in upward directed lighting due to transition to LED technology were inconsequential relative to historical variability of the halogen headlamp systems. Analysis of this data reveals trends in light distributions and can provide information for considerations of future headlamp strategies balancing the needs of drivers to illuminate potential vulnerable road users and the glare experienced by other road users.