The Lead Engineer of Forcon’s Atlanta office, John is a licensed engineer in 10 states and is board certified in forensic engineering. John has investigated over 230 pedestrian falls including 130+ slip-and-fall cases, and he is an experienced testifying expert. John is Vice-Chair of the ASTM F13 pedestrian safety standards committee, and he is Technical Contact for 2 current and 2 upcoming standards in this committee. John has been closely involved in the development of most recent US standards for pedestrian safety – working to advance the good standards and counter the marginal ones. He is also the lead engineer for a manufacturer of research-proven walkway friction testers (tribometers). John is a published author in the area of bathing surface friction and tribometer testing and has 5 years as the technical editor of an engineering journal. Given this unique experience, he has unprecedented knowledge of the strong and weak points of slip risk analysis methods in use by US experts.
Dr. Chang is an internationally known and prolific researcher in pedestrian slip-and-fall kinematics, ergonomics, and human factors. With over 120 journal and conference papers published, his research is widely cited. In Dr. Chang’s 22 years as a former Senior Research Scientist at Liberty Mutual Research Institute for Safety, he studied numerous factors that contribute to pedestrian slips. Through the use of human slip research, tribometry, and other methods, Dr. Chang’s analysis topics include walkway roughness, friction mechanisms, footwear traction, contaminants, inclines, and pedestrian perceptions of slipperiness. Dr. Chang’s experience with pedestrian slip research is unmatched.