Slip and Fall Expert Witness

John C. Sotter
President

Consultant and Expert Witness — Slip, Trip and Fall
SOTTER ENGINEERING CORPORATION

26705 Loma Verde
Mission Viejo, CA 92691-6055

TELEPHONE: 949-933-6971

Email: John.Sotter@SafetyDirectAmerica.com

Curriculum Vitae

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President John C. Sotter graduated from the University of California, San Diego (UC San Diego) in 1992 with a Bachelor of Arts in Urban Planning. His studies there included work in floor friction and chemistry.

He has 17 years of experience in responsible safety work for the City of San Clemente, California.

He has trained in floor slip resistance testing in both the United States and the United Kingdom, including training at pendulum and Tortus manufacturing facilities. He has performed most of Sotter Engineering’s floor slip resistance testing work for the past twenty-five years, conducting testing for well over 1,000 individual clients in both laboratory and field environments from Hawaii to New Hampshire, British Columbia to Mexico, New York to Florida, on the high seas, and everywhere in between. He has tested floors and road surfaces for some of the world’s largest international organizations, including Apple, Amazon, Ford Motor Company, Disney, General Motors, LAX and SEA Airports, The Ritz-Carlton, Montage Resorts, Royal Caribbean Cruise Lines, the United States Navy and United States Space Force, Carnival Cruise Lines, Virgin Voyages, Great Wolf Lodge, Porsche, Universal Studios, Unilever, Masco, and QuikTrip convenience stores, among many others.

John’s nearly forty years of experience with floor slip resistance testing using the British Pendulum Tester, Tortus Digital Tribometer, SlipAlert, BOT-3000E, and ASTM C1028 static coefficient of friction test device is virtually unmatched in the United States and the Americas. He has worked in floor friction testing and floor friction treatment throughout the United States, Canada, Mexico, and on the high seas. He also helped develop an anti-slip floor coating that has since been sold in dozens of countries.

John has testified in court once, has been deposed six times, and has participated in two mediations. He has worked with approximately one hundred attorneys on slip-and-fall matters, most of which were resolved before deposition or trial. This is likely because John relies on internationally accepted, peer-reviewed science and test methods that have been published and adopted in more than fifty nations. He is also highly knowledgeable regarding withdrawn, expired, and scientifically questionable test methods that continue to be used by many professional litigation experts whose primary expertise is often courtroom testimony rather than slip resistance science.

John performs testing for architects, building owners, flooring manufacturers, governmental agencies, and property owners, while many experts in this field work almost exclusively in litigation. His work is based on published, peer-reviewed test methods that have achieved broad international acceptance. In contrast, many commonly used American slip-resistance test methods have been withdrawn, allowed to expire, or have demonstrated significant limitations in precision and repeatability.

He frequently works behind the scenes with attorneys to evaluate opposing expert testimony and determine whether the methods, instruments, and conclusions presented are scientifically reliable. When one expert relies on internationally recognized testing methods and another relies on withdrawn standards, poorly validated instruments, or methods lacking broad scientific acceptance, disputes can often be resolved efficiently without the need for trial.

John’s background includes many miles barefoot on wet surfaces through years of competitive swimming, international sailing, water polo (including recognition as a high school All-American), and surf lifeguarding. He has traveled extensively in more than twenty-five nations. He recently made substantial revisions and updates to the American slip and skid resistance test method ASTM E303-22, which was published by ASTM in June 2022.

John has been instrumental in educating architects, building owners, flooring manufacturers, attorneys, and other professionals regarding slip resistance science and the limitations of numerous test methods that have been withdrawn or allowed to expire by organizations such as ASTM, ANSI, and other industry groups over the years.

John has published websites, articles, and educational videos explaining the distinction between internationally accepted slip-resistance science and certain testing methods that have been promoted within the United States despite limited scientific validation or international acceptance. He has been particularly active in educating architects, building owners, attorneys, and consumers about test methods that have been withdrawn, allowed to expire, or criticized for poor correlation with real-world pedestrian safety. Examples include ASTM D2047, which measures the coefficient of friction of a clean, dry surface under highly controlled laboratory conditions and does not evaluate the slip resistance of a wet walking surface. John advocates for the use of scientifically validated test methods that better reflect actual pedestrian conditions and safety risks.

He is also a member of the United Kingdom’s Slip Resistance Group (UKSRG), which conducts research into slips and falls and helps develop slip resistance standards throughout Europe. He is also one of the three founders of the American Floor Safety Alliance (AFSA), which publishes floor slip resistance test methods based on the European Union, United Kingdom, and Australian pendulum testing methodologies.

John’s participation in several international slip resistance proficiency testing programs, which included laboratories from multiple nations testing identical surfaces, has demonstrated that he is among the most precise slip resistance testers in the world today.

John calibrates pendulum testers after receiving training in the United Kingdom from a major pendulum manufacturer. He has since calibrated pendulum testers for private corporations and governmental agencies in several countries.

PUBLICATIONS: “The Floor Beneath Your Feet Has Been Compromised, and Paid Expertise Holds the Blame”, May 2026 “Specifying Anti-Slip Floor Coatings”, March 2020, pg. 24

“The New Slip Resistance Requirements in IBC,” July 2016, pg. 72.

PUBLICATIONS ABOUT ME: “John Sotter Highlights America’s Floor Problem, Striving to Redefine the Country’s Floor Safety Standards”May 2026

Numerous educational blog posts (and you should go through each of them carefully, because these are based on 40 years of John’s own research) published at https://safetydirectamerica.com/author/johnsotter/ 

Numerous educational videos published at https://www.youtube.com/user/safetydirectamerica/videos

J. GEORGE SOTTER, P.E., Ph.D.
Engineering Consultant — Slip, Trip and Fall
SOTTER ENGINEERING CORPORATION

Curriculum Vitae

Download his full Curriculum Vitae

Academic Background:  Ph.D., University of Sheffield, England
B.S., Pennsylvania State University

Recent Experience: Consultant/expert witness in slip/trip and fall litigation; experience in locations ranging from Japan and Guam to Bermuda. Project Manager and Principal Investigator of OSHA-driven one-man-year project to minimize slipping incidents on construction-site steel products. Laboratory and field testing of pedestrian surfaces for slip resistance. Consultant to Carnival Cruise Lines in slip reduction

Professional Affiliations: Member of eight national organizations, in two nations, relevant to slip resistance affiliations of pedestrian surfaces. Chairman, Ceramic Tile Institute of America’s Slip Resistance Committee

Member of American Society for Testing and Materials (ASTM) and American Society of Mechanical Engineers (ASME)

Publications:  Book, STOP Slip and Fall Accidents! 203 pp., Sotter Engineering Corporation, 2000, www.amazon.com, ISBN 0-9676030-0-5

“Specifying Anti-Slip Floor Coatings”, March 2020, pg. 24

“How to Buy Flooring Having Sustainable Slip Resistance,” The National Hotel Motel Engineer Association magazine, Winter 2011

“How to Buy Flooring Having Sustainable Slip Resistance,” U.S. Government’s Center for Disease Control, NIOSH International Conference on Fall Prevention and Protection 2010 in Morgantown, WV on May19, 2010.

“Resonant Combustion in Rockets,” Scientific American, December 1968

Author of over 35 papers, articles and other publications in technical trade magazines, international symposia, and archive journals. Includes several addressing pedestrian falling accidents

Registrations, Certifications:  Licensed as a Professional Engineer (Chemical) by State of California Board for Professional Engineers and Land Surveyors (current, since 1971), and (on as-needed basis) five other states.

Experience: More than 50 years in consulting and engineering. Slip-and-fall forensic consulting for both plaintiff and defense, in roughly equal proportions.