Evaluation of Headlamp Beam Patterns Using the Ford Chess Program

The Ford CHESS computer program was used to evaluate headlamp performance as a function of various influencing factors such as beam pattern, aim, and overall intensity. The degree to which the model was sensitive to headlamp, driver, and environmental variables was assessed. The results showed that only small increases in performance could be achieved by beam pattern modifications, improved aim, and increased overall intensity. Part of the difficulty in identifying performance improvements was found to be the low sensitivity of the CHESS figure of merit to changes in beam photometrics. Suggestions are made for upgrading the CHESS evaluation methodology to make the performance metrics more sensitive to differences in beam design.