Facts
- Michael Rix was driving a 1968 GMC pickup in Yellowstone County, Montana, when it was rear-ended by a 1978 GMC two-ton chassis-cab truck.
- The 1978 truck was sold as a chassis-cab; after sale, an authorized dealer installed a water tank on the vehicle.
- The parties stipulated that failure of a hydraulic brake line caused the brake failure at the time of the collision.
- The brake line/tube separated at the Hydrovac unit, causing loss of hydraulic braking.
- Rix sued General Motors Corporation in strict products liability alleging (1) a manufacturing defect in the brake tube/line and (2) a design defect because GMC used a single-circuit braking system rather than a safer dual-circuit system for a truck foreseeably used with heavy loads.
- GMC stipulated the brake tube was defective but contended the defect resulted from post-manufacture alteration, and denied the single-system design was unreasonably dangerous.
Issues
- Whether the strict-liability jury instructions, including the “without substantial change” requirement, incorrectly framed the plaintiff’s design-defect theory and prejudiced the verdict.
- Whether Montana Rule of Evidence 407 bars evidence of subsequent design changes in a strict products liability case.
- Whether res ipsa loquitur applies to strict products liability claims in Montana.
- Whether the trial court abused its discretion in excluding adjuster conversations, permitting cross-examination about brake-line alteration, and denying a motion to compel further discovery supplementation.
Decision
- The Montana Supreme Court reversed the judgment and remanded for a new trial.
- The court held the strict-liability instructions were erroneous and prejudicial as applied to the design-defect claim because they failed to adequately present that theory and improperly tied liability to the product reaching the user without substantial change.
- The court held Rule 407 applies to strict products liability; subsequent design changes were inadmissible to prove defect or culpable conduct.
- The court held res ipsa loquitur does not apply to strict products liability under Montana law.
- The court affirmed the challenged evidentiary and discovery rulings as within the trial court’s discretion.
Legal Principles
- In strict products liability, manufacturing-defect claims properly focus on whether the product was defective when it left the manufacturer and whether post-sale changes caused the defect.
- Design-defect claims focus on whether the product line’s design was unreasonably dangerous in light of foreseeable use; instructions that make “no substantial change” dispositive can misstate the design-defect inquiry.
- A party is entitled to jury instructions that fairly and adequately present its theory of liability; instructional error is reversible when it prevents the jury from considering a central theory.
- Montana Rule of Evidence 407 excludes evidence of subsequent remedial measures, including subsequent design changes, when offered to prove defect or culpable conduct in strict products liability.
- Res ipsa loquitur is not a separate doctrine available to establish strict products liability in Montana.
- Trial courts have broad discretion over evidentiary rulings and discovery management; appellate review is for abuse of discretion.
Conclusion
The court ordered a new trial because the jury instructions improperly constrained the design-defect theory by emphasizing “no substantial change” and failing to present whether the single-circuit brake design was unreasonably dangerous for foreseeable heavy-use configurations, while also holding that subsequent design changes are inadmissible under Rule 407 and that res ipsa loquitur does not apply in Montana strict products liability cases.