The case arose from a devastating 2017 collision on Interstate 80 in Parley's Canyon, where Raul Lopez's Volkswagen Jetta, its view of a slow-moving trailer temporarily blocked by a lane-changing vehicle, struck the rear of a utility trailer at approximately sixty miles per hour. The trailer, owned by Ron J. Peterson Construction, Inc. (RJP) and hauling a large forklift, had no underride protection. The Jetta's passenger compartment slid beneath it, killing both Lopez and his passenger, Emilio Martinez-Arroyo, instantly. Martinez-Arroyo's widow, Yesneiri Maldonado-Velasquez, sued RJP for negligence, arguing both that the company operated its equipment unreasonably and that the trailer's lack of underride guards made the crash far deadlier than it needed to be.
Writing for a unanimous five-justice panel, Justice Nielsen held that the district court made two fundamental errors: first, by applying a multi-factor policy analysis from B.R. ex rel. Jeffs v. West to negate a duty that Utah law already plainly imposed, and second, by excluding expert testimony on underride dangers on the basis of that flawed duty ruling. The court explained that Utah Code section 41-6a-1601(1)(a)(i), which bars operating a vehicle in an unsafe condition that may endanger any person, established a broad categorical duty that applied directly to RJP's operation of its truck and trailer.
The court explained that the statute protects any person traveling on a highway from the exact type of harm that allegedly occurred in this case, establishing what the court called the "broad, categorical" duty applicable here. With this categorical duty established, the court said, the duty inquiry should have ended.
The court was pointed in its criticism of the district court's analytical path. The lower court acknowledged the statutory duty existed, then proceeded to reframe it as a narrow, case-specific duty to alter the trailer and ran that reframed duty through the Jeffs policy factors, a framework the Supreme Court has reserved for recognizing entirely new categories of duty.
The court wrote that a Jeffs analysis is necessary only when a party seeks to establish a previously unrecognized duty for a category of cases, citing the court's 2024 decision in D.W. v. FPA Sandy Mall Associates. It does not apply when a plaintiff invokes a categorical duty already recognized under Utah law. The court said the district court was persuaded to go further by RJP's framing and should not have been.
The district court had also concluded that federal motor carrier safety regulations effectively capped RJP's duty at the federal minimum standard, reasoning that Utah Code section 41-6a-206, which provides that federal motor carrier regulations supercede any conflicting provisions of the state traffic code, precluded any higher state-law obligation. But the Supreme Court rejected that interpretation as a misreading of how preemption works in this regulatory space.
The court surveyed the four strains of federal preemption, express, field, obstacle, and conflict, and concluded that the Federal Motor Carrier Safety Regulations themselves establish only a conflict preemption scheme, explicitly providing that federal rules are minimum standards and do not prevent states from imposing more stringent requirements so long as full compliance with both is possible.
Justice Nielsen wrote that federal regulations in this area function as a floor, not a ceiling, citing decisions from the Fourth and Sixth Circuits as well as a Northern District of Indiana ruling, all holding that state laws imposing safety requirements beyond the federal baseline are not preempted.
"State law can impose a level of duty exceeding federal motor carrier regulations because it is possible to adhere to such a standard without making it impossible to comply with that federal floor," the court wrote. "Of course, compliance with the state duty to operate safe equipment, where there is inconsistent evidence, is a question for a factfinder." The district court's contrary conclusion, the court held, was simply wrong.
RJP argued that even if the district court erred, any error was harmless because the jury ultimately found RJP bore no fault for the collision. The court flatly rejected that argument. Because the jury reached its no-fault verdict without hearing the excluded expert testimony about the trailer's underride dangers, the court found it impossible to say the evidentiary error was harmless.
"The jury came to its no-fault verdict without what we have now held was relevant evidence about RJP's use and operation of the trailer," Justice Nielsen wrote. "This additional evidence of RJP's alleged negligence may affect a jury's assessment of, well, RJP's negligence." The court also rejected RJP's contention that enhanced-injury theories are exclusively the domain of products liability manufacturers, holding that a non-manufacturer who uses an allegedly defective piece of equipment can still face an enhanced-injury negligence claim.
The ruling carries significant practical implications for Utah tort litigation. It reinforces the court's post-Jeffs clarification that the multi-factor policy analysis for duty recognition is a tool for novel duty questions only, and that courts and litigants must resist the temptation to recast existing broad duties as narrow, fact-specific ones in order to trigger that analysis.
For practitioners handling transportation and construction equipment cases, the decision also signals that federal motor carrier compliance does not inoculate defendants from state negligence liability: meeting the federal floor is a starting point, not an ending one, and juries may still weigh whether a defendant's choices about equipment fell short of the broader common-law standard. The case now returns to the Third District Court in Summit County for a new trial.
The appeal was taken directly to the Supreme Court from the Third District Court in Summit County, where District Judge Richard E. Mrazik had presided. The Supreme Court heard oral argument on December 8, 2025, and issued its opinion on April 16, 2026. The court sat as a division of five justices pursuant to Utah Supreme Court Standing Order No. 18, reflecting a statutory change that expanded the court to seven members as of January 31, 2026.