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Judson B. Welcher, Ph.D., ACTAR

Dr. Welcher is a Biomechanical Engineer and Accident Reconstructionists at Biomechanical Research & Testing, LLC in Long Beach, CA.  He has been employed in the field of Biomechanical Engineering and Accident Reconstruction for over 28 years, specializing in trauma causation and prevention, human tolerance, restraint design, instrumented testing with humans and anthropomorphic test devices (crash dummies), accident reconstruction, and amusement park rider tolerances.


He holds a Bachelor of Science degree in Mechanical Engineering from California Polytechnic University San Luis Obispo, a Master of Science degree in Biomedical Engineering from the University of Southern California with his master’s thesis titled “Whiplash Associated Disorders: Related Anatomy, Biomechanics of Injury, and the Relationship Between Injury Potential and Automotive Seat Design”, and a Ph.D. in Biomedical Engineering from the University of Southern California with his dissertation research focused on developing and testing a new sensor for quantifying the loads within the human lumbar spine under various loading conditions.  Dr Welcher has been an accredited Accident Reconstructionist through the Accreditation Commission for Traffic Accident Reconstructionists(ACTAR) since 1995.  Dr. Welcher has taught classes in the areas of Accident Reconstruction and Biomechanical Engineering for Texas A&M Engineering Extension Services (TEEX), the Collision Safety Institute, and the Riverside Clark Training Center for Law Enforcement & Public Safety Training.


Dr. Welcher has performed and analyzed over 1000 staged instrumented human volunteer crash tests and authored over 45 technical publications and presentations on collision trauma biomechanics, injury causation, human tolerance, automotive seat and head restraint design, and accident reconstruction.  He is a member of the American Society of Biomechanics, American Society of Mechanical Engineers, Association for the Advancement of Automotive Medicine, Biomedical Engineering Society, Pi Tau Sigma Mechanical Engineering Honor Society, Society of Automotive Engineers and Southwestern Association of Technical Accident Investigators.  Dr. Welcher is a member of the ASTM International - F24 Committee on Amusement Rides and Devices.    He has tested and evaluated numerous amusement park rides and attractions across the country.  Dr. Welcher has been invited to speak at many conferences and seminars, including audiences of engineers, accident reconstructionists, law enforcement personnel, physicians, and attorneys.  Various aspects of this research have been featured on television shows such as 60 minutes, Nightline, Discovery Channel and on various news channels across the country.  


Dr. Welcher has consulted on thousands of civil and criminal forensic cases regarding aspects of both Accident Reconstruction and Biomechanical Engineering.  He has testified in local, State and Federal courts regarding Accident Reconstruction and Biomechanical Engineering from California to Massachusetts and as far north as Alaska.  Dr. Welcher has qualified and testified as an expert in over 200 trials.

Contact Information



(562) 494-4407




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