Hayes + Associates

Injury Biomechanics. Clearly Explained.


Vehicle Collisions

Low to high speed crashes; sideswipes; multiple vehicle collisions; tractor trailers; buses; ATV's & snowmobiles; rollovers;  pedestrians & cyclists; airbag, seat belt, roof crush performance; perception response time; visibility; stop light timing.

Premises Safety

Slips & falls; stairs and railings; ramps & walkways; backyard play equipment; snow and ice conditions; indoor & outdoor lighting; elevator & escalator performance; falling objects; garage door defects.


Slips & Falls

Slips, trips & falls: standing height; construction sites; stairs and ladders; assisted falls from high cliffs and buildings; floor maintenance; foreign substances; sidewalk defects.


Products Liability

Orthopedic implants; Vehicle components: roofs, airbags, seat belts. Industrial vehicles: fork lifts, boom lifts, cranes. Recreational: shoe and cleat claims; bicycle design; sports equipment.


Worker  Safety

Lifting and reaching standards; work station design; guarding; repetitive stress conditions; tool design; ergonomics and human factors; Railroad (FELA) and Shipping (Jones Act) claims.

Sports &  Recreation

Diving, skiing & terrain parks; trampolines; bouncy houses & inflatables; athletic shoes & cleats; bike, motorcycle and football helmets.


Patent Litigation

Validity & infringement analysis: orthopedic implants, including total joint replacements, fracture fixation devices; new biomaterials; bioengineered tissue replacements.

Criminal Matters

Assaults, homicides, shootings, bullet, arrow  and knife path analysis; police involved shootings; restraint conditions; child abuse; assisted falls from heights; vehicular assaults.


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Tools / Services

Hayes+Associates, Inc. is injury biomechanics and all that supports it—rigorous, evidence-based science presented clearly, so the jury understands; we do scene and incident analysis and accident reconstruction using state-of-the art, computerized simulation tools; we provide trial exhibits, 3D models and courtroom animations, all grounded in reliable engineering and physics; and we bring more than 60 years of collective experience in academic research, university teaching and forensic testimony to bear on the specific issues of our clients’ cases.  


Our Team

Wilson C. "Toby" Hayes, Ph.D

Wilson C. "Toby" Hayes, Ph.D


Wilson C. “Toby” Hayes, Ph.D., has more than 40 years of academic and consulting experience in biomechanics, orthopaedic research and injury reconstruction, nearly 20 years of it teaching anatomy at Harvard Medical School and bioengineering at MIT.


Erik D. Power,  P.E.

Professional Engineer

Erik D. Power, M.S., P.E., consults in the areas of vehicular accident reconstruction and injury biomechanics. He is a Registered Professional Mechanical Engineer in the State of Oregon, and a Fully Accredited Traffic Accident Reconstructionist.


Kristen E. Lipscomb, Ph.D.

Biomedical Engineer

Kristen Lipscomb, Ph.D. consults in the areas of injury biomechanics, orthopaedics, fall biomechanics, and motor vehicle collision reconstruction. She is a Fully Accredited Traffic Accident Reconstructionist and is a Certified XL Tribometrist.



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