Task 81, FY 1997, "The Relationship Between Headlamp Design and Retroreflective Sign Visibility" (Westat, Inc.). The visibility and legibility of unlit signs at night are fundamentally linked to the characteristics of vehicle headlamps. Headlamps also illuminate pedestrians, with the light above the plane of the headlamp being particularly important for viewing the head and torso. The light above the horizontal plane, however, produces glare for oncoming motorists and, through mirror reflection, to downstream motorists. Headlamps also provide a visual cue at night to other road users that helps them locate the approaching vehicle's relative position and decide whether it is safe to enter or cross the roadway. Headlamp designs impact the styling and cost of vehicles. Balancing these disparate interests is a complex task. The objective of this project was to recommend headlamp intensity requirements above the horizontal plane of the headlamp. The report has been delivered to AASHTO. (NCHRP Staff: B.R. Derr)