Thirty-eight participants viewed pavement markings of 4, 6, and 8 inches wide one at a time while driving on the Virginia Smart Road. The distance at which participants could detect the marking was measured. The procedure was performed with two vehicle types (truck and sedan) with both a high and low ambient lighting condition. The results show that a wider pavement marking has an increased detection distance. However, the benefit of increased detection distance appears to be limited at an undetermined critical width. The luminance of the markings was measured from the overall mean detection points for each width of material. These results and a calculated dosage factor were also analyzed. The dosage factor, which is the product of the solid visual angle of the marking and the luminance, showed some relationship to the threshold conditions, however it was not consistent across vehicle types. The results suggest that further research is required in order to closely define an optimal marking width. In addition, further research should continue to explore the implications of the dosage factor.
Abstract