Rule 407.
When measures are taken that would have made an earlier injury or harm less likely to occur, evidence of the subsequent measures is not admissible to prove:
• negligence;
• culpable conduct;
• a defect in a product or its design; or
• a need for a warning or instruction.
But the court may admit this evidence for another purpose, such as impeachment or—if disputed—proving ownership, control, or the feasibility of precautionary measures.
([Pub. L. 93–595, § 1], Jan. 2, 1975, [88 Stat. 1932]; Apr. 11, 1997