Junior Williams, while riding his Kawasaki motorcycle, collided with a Jeep, which was making a U-turn at an intersection in Springfield, Massachusetts. His motorcycle struck the passenger-side door and slid under the Jeep. The motorcycle’s fuel tank burst, and a fire ensued. Williams’ expert determined that during the accident, the right-side frame weld failed, allowing the frame to puncture the gas tank, which released the fuel that started the fire.  He further noted that the right-side frame weld on Williams’s motorcycle was (1) smaller and (2) weaker than the corresponding weld on an exemplar motorcycle and the matching left-side frame weld on Williams’ motorcycle.  The District Court excluded the expert’s testimony under Daubert, and then granted summary judgment in favor of the defendant.

The U.S. First Circuit affirmed the dismissal, but on slightly different grounds:

“Dr. Rondinone was Williams’s sole expert witness on liability, and he did not offer an opinion that the alleged defect in the right-side frame weld caused the weld to fail when it otherwise would not have. Indeed, Dr. Rondinone conceded during his deposition that he had not ‘done any analysis’ to determine whether ‘some significant forces were experienced by the entire front end of that motorcycle that would have fractured even a proper weld,’ and he stated that he ‘couldn’t say whether the forces during the impact would have been enough to break a proper weld.’ At deposition, he also admitted that he ‘couldn’t tell whether the forces seen by the weld in this accident exceeded the forces necessary to fracture a proper weld.’ It is possible to glean from Dr. Rondinone’s testimony the seeds of a more nuanced theory of causation. While Rondinone conceded that he did not know if a proper right-side weld ‘would have fractured’, he also stated that a proper weld – if it fractured – would have fractured in a different direction: ‘through the base material.’ Williams, though, did not advance below and does not advance on appeal this more precise reading of Dr. Rondinone’s testimony. More importantly, Dr. Rondinone never closed the causal loop by opining that, had the right-side weld fractured through the base material, the fire would most likely not have occurred.

“Williams argues that he can show causation because ‘there is no question that the subject weld on the motorcycle failed, puncturing the fuel tank resulting in a fire that injured Junior Williams.’ Even assuming arguendo that this conclusion is well-supported by the record and Dr. Rondinone’s testimony, Williams’s argument misses the relevant causation question. The causation question in this case is not whether the right-side frame weld’s failure caused Junior Williams’s injuries; rather, the relevant question is whether the alleged manufacturing defect to the right-side frame weld caused the injuries. Dr. Rondinone admitted that he could not offer an opinion on whether a properly manufactured weld would have failed in this accident. His testimony failed to establish the necessary causal link between the manufacturing defect and Junior Williams’s injuries.”


Williams v. Kawasaki Motors, 30 F.4th 66 (1st Cir. 2022).