Falls are a major contributor to construction-related fatalities. Many construction fall fatalities occur during roofing, and may be prevented by proper use of fall protection. A prevalent option for fall protection is a personal fall arrest system (PFAS). However, full adaption of PFAS is hindered by usability issues, particularly in the harness component. Current research aims to develop design requirements for more usable fall arrest harness. A study was conducted to consider the inter-relations of objective measures of fit and strap pressure, along with subjective usability measures including discomfort ratings and post-task questionnaire responses. 18 local roofers were recruited to test three different harnesses, while performing both quiet calibration-oriented trials and simulated roofing tasks. Significant correlations between discomfort ratings and pressure values were found only in quiet trials. Questionnaire responses were validated by inter-correlations and by significant correlations with discomfort ratings. Multiple comparisons of objective fit values and questionnaire responses revealed deficits in the low-end harness, while suggesting few differences between the mid- and high-range harnesses. Results from analysis of both objective and subjective measures were considered alongside free-response prompts to develop a set of four requirements for consideration in future harness design, including a lowered harness weight, an intermediate level of padding, inclusion of rolling style vertical strap quick-adjusters, a belt-style thigh strap adjustment mechanism, and the adoption of a three-sized sizing scheme. / Master of Science