In 1976 a photometric evaluation of reflective sheetings was begun. Included in the study were 9 white and 10 yellow reflective sheetings. For each color, five 15-in. Square aluminum-backed panels were prepared and placed on vertical racks on the sign shop roof in wisconsin rapids, wisconsin. The panels were first put in place near the end of january 1977. From 1977 to 1982, semiannual photometric evaluations of the sheetings were performed with a photometer. From 1983 to 1987, annual reflectivity measurements were obtained with a retroreflectometer. The amount of cold cracking also was measured. All photometer and retroreflectometer tests were taken at a divergence angle of 0.2 Deg and at incidence angles of -4 and +30 deg. In addition to the five panels for each color sheeting, each white sheeting had five panels prepared for the purpose of studying the effect of stone bruising on cold cracking. Artificial stone bruises were made oneach of these panels (four bruises per panel, one bruise per quadrant) by means of a dull center punch. (The artificial bruise damaged the sheeting but not the aluminum.) This paper appears in transportation research record no. 1316, Visibility for roadways, airways, andseaways 1991: proceedings of a conference, july 25-26, 1990, washington, d.C.
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