Download or read book Retroreflective Requirements for Traffic Signs - a STOP Case Study. Final Report written by Juan M. Morales and published by . This book was released on 1987 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study determined the performance of STOP signs based on their retroreflective properties. Thirty-five 30-inch STOP signs, including engineering grade and high intensity, were measured in the laboratory to determine their retroreflective properties. A subset of ten signs was taken to the field to determine how far they could be recognized by paid subjects. Mathematical relationships between the various retroreflective properties and recognition distance were developed. The overall specific intensity per unit area (SIA) was found to be a good measure for estimating the recognition distance of STOP signs.