The contact owns a 2012 Hyundai Sonata Hybrid. The contact stated that after parking in the driveway and turning the vehicle off, the husband exited the vehicle and walked around to the passenger side. After opening the front passenger-side door, the vehicle erroneously rolled backward down the driveway and crashed into a tree. During the incident, the husband was knocked to the ground and dragged 20 feet down the driveway. During the incident, the husband sustained a head bruise and laceration, an injured leg, and an injured arm. The front passenger also sustained bruised ribs, a head and left knee injury from the vehicle crashing into a tree. Both persons required medical treatment. The cause of the failure was not determined. The vehicle was not repaired. The manufacturer and local dealer were notified of the failure but no assistance was offered. The contact was informed that the vehicle was not included in the NHTSA Campaign Number: 14V434000(Power Train). The failure mileage was 112,000.