## Facts

- A late-night multi-vehicle collision occurred on U.S.-127 in Jackson County, Michigan on May 26–27, 1962.
- John Gutekunst drove a northbound Ford Galaxie convertible with a passenger; Robert Emmons followed closely behind in a northbound Pontiac carrying Mrs. O’Dowd.
- Gutekunst testified he saw headlights of an oncoming car turning toward him near the Loomis Road intersection, swerved right with a wheel on the shoulder, and was then struck from behind.
- A southbound Cadillac driven by Dana W. Linehan collided with Emmons’s Pontiac; the crash caused fatalities, including Mrs. O’Dowd.
- Mrs. O’Dowd’s estate filed a wrongful death action alleging Linehan’s Cadillac was in the wrong (northbound) lane at impact.
- At trial, the defense presented accident-reconstruction expert William E. Billings, who offered opinions about point of impact and lane position based on a later investigation and assumptions about vehicle movements.

## Issues

1. Whether the trial court committed prejudicial error by admitting accident-reconstruction opinions on point of impact and lane position where the opinions lacked an adequate factual foundation and rested on speculative assumptions.

## Decision

- The Michigan Supreme Court reversed the Court of Appeals and the circuit court judgment for the defendant.
- The Court held that substantial portions of Billings’s reconstruction testimony were improperly admitted because they were speculative and not sufficiently grounded in record evidence.
- The Court remanded for a new trial because the erroneous admission concerned the central disputed fact (which vehicle was in the wrong lane) and was not harmless.

## Legal Principles

- Expert accident-reconstruction testimony is admissible only when supported by a demonstrably adequate factual foundation in the record; opinions based on assumptions not established by evidence are inadmissible.
- Reconstruction opinions derived from altered or uncertain scene conditions and unsupported estimates of speeds, distances, or vehicle dynamics risk being speculative rather than helpful.
- Expert opinion that effectively resolves the key factual dispute (e.g., lane position or point of impact) is especially problematic when the expert’s methodology and premises are disputed or inadequately supported, because it may improperly displace the jury’s role.

## Conclusion

The court ordered a new trial in a wrongful death automobile-collision case because the defense accident-reconstruction expert’s opinions on point of impact and lane position lacked a reliable evidentiary foundation and likely affected the verdict on the central liability question.


O’Dowd v. Linehan, 385 Mich. 491, 189 N.W.2d 333 (Mich. 1971)