The court addresses the application of Rule 26(b)(4)(D) (one independent expert per issue per side) when a percipient witness also testifies as an expert.

Plaintiffs sued for personal injury and wrongful death arising out of an automobile accident. At trial their attorney elicited from the police accident reconstructionist his conclusion as to the defendant’s speed. When the plaintiffs called their own expert the trial court allowed his testimony on a different issue but restricted or limited it as to speed because the officer had already testified as an expert. Defendants won the jury’s verdict; plaintiff’s appealed.

The Court of Appeals reverses and remands (though at the end it affirms a couple of rulings relevant on remand that we won’t cover here).

Plaintiffs first argued that an “actor or viewer” witness, to use the court’s language, can’t be considered an “expert.” The court concludes that such a witness can be and was here (the defendants apparently did not dispute that the officer was qualified to give expert testimony).

The question becomes whether he was an “independent” expert. The Committee Comment to the rule clearly defines an “independent” expert as a “retained” expert and not a percipient witness. The Court of Appeals decides that “independent” is nevertheless ambiguous but that because earlier  decisions have relied on these Committee Comments it will as well “although no direct authority requires us to do so.”  (The court is of course correct in that regard; we have long complained about rule comments, as in this case, which we don’t know why the court here didn’t cite.) So it concludes that the officer was not an “independent” witness and therefore that the rule doesn’t bar his testimony.

The defendants fall-back argument was that since the officer had already testified on the subject, speed evidence from the plaintiff’s expert would be cumulative. But their expert used a different method to arrive at his opinion and had the car traveling at different speed than the officer did.