Farmer Brown's Wagon

Farmer Brown has sued Joe Deer Co. for designing, manufacturing, and selling a defective farm wagon. Plaintiff's evidence at trial has tended to prove that while running a corn chopper with a farm wagon attached to catch the corn, the brackets that help support the wheels on one side of the farm wagon broke off and caused the wagon to collapse, injuring the plaintiff. Plaintiff's theory is that the wagon, which he purchased 15 years before the accident, should have lasted at least 25 years, and that Deer should be liable because it did not notify plaintiff prior to the accident that it had developed stronger brackets since plaintiff's purchase.

At trial, plaintiff offers evidence that after plaintiff had purchased his wagon and before the accident Deer had redesigned the support brackets to make them stronger. Deer not only used the stronger brackets in new wagons, it also sold the new stronger brackets to farmers who needed to replace the brackets on their wagons. Deer notified its dealers of such parts but did not notify the farmers directly. Plaintiff also has experts who will testify that the stronger brackets on the modification would not have broken like the original weaker ones did.

Deer objects to the admission of this evidence under Rules 407, 402 and 403. Deer's witnesses will testify that the redesign of the inner and outer brackets was incidental to the redesign of the lubrication system (not an issue in Brown's accident) and was not related to any accidents or known problems with the brackets. Deer concedes that it would have been feasible to design and manufacture the brackets in the new, stronger way when the plaintiff's farm wagon was manufactured. Deer states that it did not notify the farmers of the subsequent modifications because there had been no problem with the original brackets in any of the more than 12,000 farm wagons sold.

What ruling on plaintiff's offer and why? What are the policy arguments for exclusion or admission of this evidence?