Hamer v. Duffy, Cornerstone Poured Foundations, Inc.

2026 S.D. 4 (S.D. 2026) · Supreme Court of South Dakota · February 4, 2026 · No. 30776

Summary

The Supreme Court of South Dakota reviewed a personal-injury action arising from an automobile collision involving an employee of Cornerstone Poured Foundations, Inc. The court held that the circuit court properly denied amendment of the complaint to add direct-negligence claims against Cornerstone because of prejudice, but abused its discretion by denying amendment to identify alleged Federal Motor Carrier Safety Regulation violations related to the driver’s existing negligence claims. The court also addressed the exclusion of expert testimony and the refusal to give a jury instruction concerning 49 C.F.R. § 392.3.

Holdings

  1. The circuit court did not abuse its discretion in denying the eve-of-trial amendment adding claims for negligent entrustment, retention, supervision, and training against Cornerstone because the amendment introduced substantially different theories of liability, would require additional discovery and defenses, and would prejudice Cornerstone.
  2. The proposed allegations that Duffy violated FMCSRs adopted by South Dakota were not futile. Those regulations may establish the standard of care for common-law negligence claims against commercial motor-vehicle operators, and an unexcused violation may constitute negligence per se.
  3. The circuit court abused its discretion by excluding Grill's testimony because his specialized knowledge concerning commercial motor vehicles, commercial-driver requirements, FMCSRs, and the heightened skills needed to operate such vehicles would assist the jury in evaluating negligence and comparative fault.
  4. The circuit court abused its discretion by excluding DiTallo's testimony because his specialized opinions concerning reaction time, vehicle speed and distance, attentiveness, avoidance, and the mechanics of the collision would assist the jury in evaluating negligence and comparative fault.
  5. The exclusion of Grill's and DiTallo's testimony was prejudicial because there was a reasonable probability that the testimony could have affected the jury's assessment of whether Hamer's contributory negligence was more than slight.
  6. The circuit court abused its discretion by refusing to instruct the jury on 49 C.F.R. § 392.3 because the regulation was adopted through SDCL 49-28A-3, related directly to Hamer's pleaded allegation that Duffy failed to remain vigilant, awake, and alert, and stated applicable law supported by the evidence.

Questions Presented

  1. Whether the circuit court abused its discretion by denying Hamer's motion to amend the complaint to add direct-negligence claims against Cornerstone and allegations that Duffy violated the FMCSRs.
  2. Whether the circuit court abused its discretion by excluding the expert testimony of Adam Grill and Michael DiTallo.
  3. Whether the circuit court abused its discretion by refusing to instruct the jury that 49 C.F.R. § 392.3 supplied an applicable standard of care and that its violation could constitute negligence.

Disposition

reversed_and_remanded

Cases Cited (24)

  • Ries v. JM Custom Homes, LLC, 2022 S.D. 52, ¶¶ 11-12, 980 N.W.2d 217, 221-22(followed)
  • Prairie Lakes Health Care System, Inc. v. Wookey, 1998 S.D. 99, ¶ 29, 583 N.W.2d 405, 417(followed)
  • In re Wintersteen Revocable Trust Agreement, 2018 S.D. 12, ¶ 33, 907 N.W.2d 785, 795(followed)
  • Bell v. Allstate Life Insurance Co., 160 F.3d 452, 454 (8th Cir. 1998)(followed)
  • Highmark Federal Credit Union v. Hunter, 2012 S.D. 37, ¶¶ 11-17, 814 N.W.2d 413, 416-18(distinguished)
  • Levene v. Staples Oil Co., 685 F. Supp. 3d 791, 808-10 (D.S.D. 2023)(followed)
  • Schmidt v. Royer, 1998 S.D. 5, ¶¶ 21-22, 574 N.W.2d 618, 624(followed)
  • Thompson v. Summers, 1997 S.D. 103, ¶ 16, 567 N.W.2d 387, 393(followed)
  • Fritz v. Howard Township, 1997 S.D. 122, ¶ 16, 570 N.W.2d 240, 243(followed)
  • NFI Interactive Logistics LLC v. Bruski, 239 N.E.3d 63, 75 (Ind. Ct. App.)(persuasive)

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