A series of studies were designed and conducted to evaluate passenger car and truck mirror configurations and convex mirror radii of curvature and to identify the most effective mirror systems for actual on-the-road use. The studies were conducted in two phases, during which over 40 combinations of mirror convexities and mirror configurations were evaluated experimentally. Phase 1, which is reported in Volume 1, was directed toward investigating the effect of mirror convexity on driver judgments of adjacent lane following vehicle speed, distance and accepted lane change gap size. The convexity(s) resulting in the best performance were to be used in subsequent on-the-road performance tests. Mirrors of 20, 40, 55 and 80 inch radii of curvature were fabricated in several configurations specifically for a passenger car, light pickup truck and a van. Configurations ranged from viewing the proposed FMVSS 111 passenger vehicle (PV) targets with plane mirrors and convex mirrors of varying radii to mirror systems viewing the truck (TRK) targets with a single mirror of varying convexity or a combination of plane and convex mirrors viewing those targets separately. Male and female drivers under 30 and over 50 years of age provided over 12,000 speed and distance judgments. Results indicated that performance differences between mirror convexities were small and generally not significant because of extensive practice. Since the 80 inch radii mirrors produced large obscurations in the forward field of view (FOV) and since some of the 20 inch radii mirrors yielded significantly poorer performance and all such mirrors were rated low by drivers, convexities selected for further study were those of a 40 and 55 inch radii.
Abstract