Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Safety Sciences

First Advisor

Majed Zreiqat

Second Advisor

Helmut Paschold

Third Advisor

Christopher Janicak


This study examined and evaluated exit signs and related flashing way-finding technology (Linear Strobe™ L-100). The research determined exit sign performance and an observer’s preference in two phases. The photometric phase measured and recorded luminance and luminance contrast levels for exit signs (red LED, green LED, blue LED, photoluminescent or PLM, and flashing way-finding at a distance of 100 feet using a photometer across four combined conditions of ambient lighting and obscurity (#1 lights on-no smoke, #2 lights on-smoke, #3 lights off-no smoke, and #4 lights off-smoke). The photometric phase results determined the red and green font had the highest luminance overall and the highest luminance contrast for the green font and flashing. The flashing technology had the lowest luminance levels overall but had the highest luminance contrast when smoke was present (conditions 2 and 4). Observers determined their individual preferences under the same four conditions as the photometric phase and their overall preference regardless of condition. A significant difference was reported for the flashing technology for conditions 2, and 4 and red font for condition 1 (p = .000). Thus, flashing way-finding performed better with smoke. Regardless of condition, 72% of males and 54% of females preferred flashing resulting in 63% of all observers preferring the flashing technology overall. Consideration of these results indicated greater luminance levels did not equilibrate to better visibility or overall preference. Flashing was preferred under the conditions with smoke where luminance contrast was highest. Qualitatively, the flashing technology appears to be enhanced by the smoke concentrations where the traditional exit sign was obscured. This study is important given no research to date has been performed with the Linear Strobe™ as compared to existing exit signs. Exit sign “readability” criterion could become obsolete as the flashing outline of the door is easily perceived as an exit below the smoke layer. This technology should be studied further and considered as a more universal design for children, elderly, color-blind, and prescriptive eye wear users than the traditionally worded “EXIT” sign.

Available for download on Thursday, December 05, 2019