D was driving her parents' car when she pulled in front of Harder's (P), who swerved violently to avoid a collision. This evasive maneuver overturned P's vehicle. P and his wife were not wearing their seatbelts and were thrown from their car. Ps suffered severe orthopedic injuries as a result of the accident. Ps sued D. D sought information concerning Ps' use and experience with seat belts and shoulder restraints. P objected, and D moved to compel discovery. The trial judge denied the motion and issued a protective order. D filed a special action petition. The court of appeals vacated the trial judge's protective order and held that evidence of seat belt nonuse was admissible so long as D could demonstrate a causal relationship between the nonuse and the injuries. The court concluded that under the doctrines of avoidable consequences and mitigation of damages, motorists were responsible to take reasonable pre-accident measures to prevent or reduce damages from foreseeable injury. Failure to avoid or mitigate foreseeable damages would result in a corresponding reduction in the damages awardable. The court found that the absence of a mandatory state seat belt law did not negate the duty to mitigate damages. P appealed.