Description

AASHTO T 257 – Standard Method of Test for Instrumental Photometric Measurements of Retroreflective Materials and Retroreflective Devices

This standard covers procedures for instrumental determinations of photometric characteristics of retroreflective materials and retroreflective devices.

This method describes procedures used to measure photometric quantities that relate to the visual perception of retroreflected light. The most significant usage is in the relation of the nighttime vehicle headlamps, retroreflector, and driver’s eye geometry.