It has been suggested that closed head injury can occur during low-to-moderate speed rear-end collisions. Despite this suggestion, there exists no prior studies that support or deny this position. Head restraints are designed to halt the motion of the head during a rear-end collision in order to prevent excessive deformation of the cervical spine. This rapid deceleration of the head may have the potential for closed head injury. The objective of the current study was to evaluate publicly available rear-end crash test data to determine the accelerations acting on the head in a wide range of vehicle types.
A total of 42 rear-end collision crash tests with 53 anthropometric test dummies were evaluated. Of the 53 dummies, 32 were positioned in the driver’s seat, 6 in the front passenger’s seat, and 15 in the right-rear seat. 45 were instrumented 50th percentile male and 8 were instrumented 5th percentile females. Linear acceleration in the x, y, and z directions were recorded during each test for each dummy. Additionally, the head injury criteria (HIC) was calculated for each test and each dummy. Student t-tests were performed in order to determine statistically significant differences (p
In general, the values were consistently below previously reported concussion tolerance values and Injury Assessment Reference Values provided in the Federal Motor Vehicle Safety Standards (FMVSS). The increased magnitude of linear head acceleration for rear-seat occupants was most likely the result of a stiffer head restraint construct. Interestingly, this increase in resultant head acceleration most likely occurred over a very short duration, since there was no statistical significance in the HIC values. The results from the current study indicate that moderately severe rear-end collisions do not generate forces consistent with closed head injury.