South Dakota Supreme Court: Federal Trucking Regulations Set the Standard of Care After Intersection Crash

On the morning of April 9, 2019, Justin Hamer was driving west on 271st Street near the Interstate 29 interchange in Lincoln County, South Dakota, when he reached an intersection where the traffic signal was flashing red. He stopped. Paul Duffy, operating a commercial truck for his employer Cornerstone Poured Foundations, Inc., approached from the opposite direction and turned left toward the I-29 on-ramp. Duffy's truck struck Hamer's pickup. No citations were issued at the scene, and each driver claimed the other failed to yield.

Hamer and his wife Kim filed suit against Duffy and Cornerstone. During pretrial proceedings, Hamer moved to amend his complaint to allege that Duffy violated the Federal Motor Carrier Safety Regulations (FMCSRs) that South Dakota has adopted into state law under SDCL chapter 49-28A, including 49 C.F.R. section 392.3, which prohibits a commercial driver from operating while fatigued or impaired. Evidence showed Duffy had worked 13-hour days and slept only 6.5 hours in broken shifts before the collision. The circuit court denied the amendment and excluded both of Hamer's expert witnesses.

Scott Hoy and James Hoy of Hoy Law in Sioux Falls, along with co-counsel Danny Ellis, tried the case and pressed every issue on appeal. The jury, without the benefit of the excluded experts or a fatigue instruction, found both drivers negligent but assigned Hamer's fault as more than slight under South Dakota's comparative negligence bar, awarding him zero damages.

The South Dakota Supreme Court reversed on three grounds. First, the circuit court abused its discretion by excluding commercial vehicle safety expert Adam Grill. Grill would have testified about the CDL-specific training standards and performance requirements that apply to commercial drivers beyond ordinary traffic law, and the court found that testimony would have assisted the jury. Second, accident reconstructionist Michael DiTallo's opinion, that Duffy had between 4.4 and 4.9 seconds to perceive and react to Hamer's vehicle and nonetheless failed to yield, should also have been admitted. Third, the trial court erred in refusing a jury instruction on 49 C.F.R. section 392.3.

The court's most consequential holding was on the FMCSR issue. Because South Dakota adopted the federal regulations by statute, unexcused violations of those regulations can establish negligence per se, meaning the jury would be permitted to treat a proven FMCSR violation as a breach of the legal duty of care without needing additional proof of unreasonableness. The opinion, authored by Justice Devaney and joined without dissent by Chief Justice Jensen, Justices Salter and Myren, and retired Justice Kern, affirmed the denial of Hamer's separate bid to add direct negligence claims against Cornerstone but reversed on the expert and instruction rulings, remanding the case to the circuit court for further proceedings that reopen it for a new trial.