This paper presents the results of three studies conducted by using the Ford Comprehensive Headlamp Environment Systems Simulation (CHESS) model. This model provides a much broader, more comprehensive and more economical computerized method for measuring head lighting performance than the traditional seeing distance field tests. The model was developed from an extensive program including nighttime field tests, traffic surveys and analysis and applications of earlier research work.The first study was conducted to determine the effect of horizontal and vertical aim on the visual performance of low beams. The second study was conducted to evaluate the effect of headlamp mounting height on low beam performance. The third study was conducted to correlate the performances of various existing and experimental low beam systems with their beam patterns.