Impacts of Fog Characteristics, Forward Illumination, and Warning Beacon Intensity Distribution on Roadway Hazard Visibility

Figure 2

RVP values for a standard 20 cm × 20 cm visibility target [14] viewed from 46 m as a function of background luminance and contrast. An RVP value of 0 corresponds to the threshold for object identification; negative values (not shown) are possible for objects that can be detected but not identified. RVP values less than 0.8 are considered unsatisfactory for driving safety because small reductions in target contrast or target size will render potential hazards invisible.