Seventh Circuit Finds Expert Testimony About the Need for an Independent Service Brake Was Improperly Excluded in Lawsuit Over Lawnmower Accident
It’s pretty rare for an appellate court to reverse a trial court’s ruling deeming expert opinion testimony inadmissible under Federal Rule of Evidence 702. That makes the recent opinion of the Seventh Circuit in Hillman v. Toro Company, 2026 WL 157664 (7th Cir. 2026), the exception to the rule, and that’s in part because the trial court bypassed the issue entirely.
In Hillman,
Rebekah Hillman lost her left leg below the knee in a riding lawnmower accident. Rebekah, her wife Jennifer Hillman, and their minor daughter P.J.H. sued the manufacturer of the mower, The Toro Company, alleging that the mower’s design was defective in several ways. According to the Hillmans, the mower should have had a mechanical brake independent of the hydrostatic transmission or an interlock ignition system, either of which would have prevented the accident, and/or a rollover protection system for rider safety in the event of a crash.
In response, “[t]he district court excluded all of the Hillmans’ expert evidence as unreliable or irrelevant and therefore granted Toro summary judgment.”
On appeal, the Seventh Circuit started by noting the typical rule that “[w]e apply an abuse of discretion standard of review and ‘shall not disturb the district court’s findings unless they are manifestly erroneous.'” But it then added that
To earn deference, however, the district court must show its work….We review de novo whether a district court has followed Rule 702’s framework for evaluating expert evidence….Announcing that a particular expert opinion ‘simply does not pass the Daubert test’ is a conclusion—not an analysis—to which we owe no deference.’ Our threshold review is not exacting, but it is granular. Where an expert report contains multiple opinions, deference is due only for the district court’s decisions on the opinions it satisfactorily addresses.
The Seventh Circuit then focused on proffered testimony by the plaintiff’s expert witness, Thomas Berry, that “the Timecutter was defective and unreasonably dangerous because it lacked an independent service brake, which would have prevented the accident entirely.” It found that “Absent from the district court’s discussion of Berry’s report, however, is any analysis of his opinion on the lack of an independent brake.”
The court this assessed the admissibility of this testimony de novo and concluded that
Berry’s opinions on an independent brake are admissible under Rule 702 because they are both relevant and reliable. Berry’s opinions are relevant both to the risk-utility test that governs the strict liability theory and to whether Toro breached its duty of care to the Hillmans in designing the Timecutter, part of the negligent design theory. Specifically, Berry opined that the Timecutter’s lack of an independent brake made it “defective in design and unreasonably dangerous,” and also that Toro “knew or should have known of technically and economically feasible design alternatives that would have significantly reduced the risk without adversely affecting the utility of the machine.” Berry identified several such alternatives. He reported that at least one other zero-radius-turn mower manufactured by Toro had an independent brake. He also reported that Hydro-Gear, the company that made the hydrostatic motor used in the Timecutter, “had available a disc brake design that could have been utilized.” Berry also identified two other zero-radius-turn mowers with independent brakes. One was a John Deere model with a “simple park brake” that “uses a lever to rotate two steel pawls against the rear tires” and withstands slopes of up to 30 degrees—greater than three times the slope of the Hillmans’ lawn, at 9.5 degrees. He also identified a “more sophisticated brake system…such as that provided by Scag on its Patriot and Freedom Z mower,” the latter being “only slightly bigger than the Toro Timecutter.”
The court thus reversed the trial court’s ruling granting the defendant summary judgment.