Minor neck injuries (whiplash associated disorder) during rear-end impacts have become the most frequent cause of permanent disabilities compared with rear-end impact injuries in other regions of the body. The social cost of these types of injuries have grown to be such an extensive burden that identification and clarification of the mechanism of neck injury, as well as the need for a method for evaluating the reduction of neck injuries through the use of an advanced seat and headrest, becomes imperative. Injury evaluation parameters were set using a human finite element model based on live volunteer and cadaver experiments, reinforced with data from 20 accidents. It is found that the displacements between the cervical vertebrae can cause neck injuries/persistent symptoms, and 2D strains of the inter-vertebral bodies as injury criteria are defined. The thresholds where WAD2+ injuries occur by making risk curves with NIC and the neck forces, and lead to a proposed neck injury evaluation method.