Vehicle-Specific Headlamp Mapping for Nighttime Visibility

Understanding when an object enters into the headlamp projection from a vehicle is useful to assist the driver in detecting the object in dark or nighttime conditions. Understanding the specific illumination pattern of a vehicle headlamp beam is useful for the evaluation of nighttime visibility issues in accident reconstruction. Determining when an object entered in the headlamp beam at a specific illuminance may be of particular importance to driver avoidance capabilities. Headlamp illumination patterns may be unique to each vehicle make and model. In this study, the headlamp illumination patterns of multiple vehicles were mapped, and the measured illumination distances were compared with empirical predications. In general, individual headlamp illumination distances fell within the range of minimum and maximum empirical predictions. However, the empirical relationships can have large standard deviations, which may influence the available time for the driver to detect and respond to the object. Mapping the headlamp illumination pattern of a specific vehicle increases precision of illumination distance measurements. Several sets of duplicate exemplar vehicles (identical make, model and model year) were included to evaluate consistency in headlamp illumination distance. Additionally, a vehicle make and model may have different headlamp options, which affect the headlamp pattern. The importance of ensuring the proper headlamp type on a tested vehicle is presented. The results indicated that headlamp illumination distance for vehicles of identical make, model, and mode year grouping are substantially similar. This finding is useful in that if a subject vehicle is not available, the headlamp illumination distance of a similar exemplar vehicle can be considered representative.