Final answer:
The priority intervention is to initiate transfer to a trauma center.
Step-by-step explanation:
The priority intervention when significant abdominal and pelvic injuries are noted in the primary survey of a passenger brought to the ER following a high-speed MVC is to initiate transfer to a trauma center. This is because trauma centers have specialized resources, personnel, and equipment to provide comprehensive care for critically injured patients. Transfer to a trauma center allows the patient to receive prompt and appropriate surgical interventions if needed and improves their chances of survival.