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Over half of the 1.2 million annual traffic fatalities worldwide are pedestrians struck by motor vehicles [ 1 ]. Medical databases, such as the National Inpatient Sample (NIS), have been utilized to ascertain injury patterns in the general population of injured pedestrians [ 2 - 3 ]. However, the authors are not aware of any studies investigating how factors, such as physical impairments, intoxication, and pre-existing medical implants (e.g. hip replacement, artificial knee, etc.) affect the prevalence of pedestrian accidents or injury outcomes. Five to eight million inpatient hospitalization records are included in the NIS annually, and this large sample size allows for analyses that are not possible with smaller data sets on pedestrian injuries. The current study utilizes the NIS to evaluate how several factors such as blindness, deafness, intoxication, and pre-existing medical implants affect injury patterns when compared to the general population of hospitalized pedestrians.

The risk of sustaining injury in side collisions is correlated to collision severity as well as other factors such as restraint usage and occupant position relative to the impact. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2007) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) either between 8:00 and 10:00 or between 2:00 and 4:00, indicating a side impact collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on resultant delta-V, restraint system use, and occupant position relative to the impact.

The risk of sustaining injury in frontal collisions is correlated to collision severity as well as other factors such as restraint usage and airbag deployment. Eleven years (1997 to 2007) of National Automotive Sampling System (NASS) data from the Crashworthiness Data System (CDS) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) between 11:00 and 1:00, indicating a frontal collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on factors such as delta-V, restraint system use, and airbag deployment. Each body region (head, face, spine, thorax, abdomen, upper extremity, and lower extremity) was considered separately.

Previous studies have suggested injury assessment reference values (IARVs) for lower neck injury based on scaled upper neck values. This study developed independent flexion and extension IARVs for the lower neck by matching Anthropomorphic Test Device (ATD) data to impact-tested post-mortem human subjects (PMHSs) with mid- to low-cervical spine injuries. Pendulum and sled tests with Hybrid III midsize male and small female ATDs were run under conditions mimicking those of published PMHS torso drop-sled tests and other PMHS studies. Measurements included upper and lower neck forces and moments, head acceleration, head rotation rate, and head/neck angles for the pendulum tests. Rear impacts corresponding to rigid seatback tests without a head restraint produced lower neck extension moments that increased dramatically with test severity, as measured by increasing delta-V and/or decreasing pulse duration.

Vehicle aspect ratio has been reported as a significant factor influencing the likelihood of fatality or severe injury/fatality during single-vehicle rollover crashes. To investigate this, dynamic simulations of friction-induced rollover accidents were performed using different roof heights, but otherwise identical vehicle parameters and initial conditions. Higher aspect ratios tended to cause the leading side roof to impact first, with significant impact force. The roof impact forces during the first roll of higher-roofed vehicles were primarily laterally directed with respect to the vehicle. Impact locations during subsequent rolls were less predictable. Lower aspect ratios produced higher impact forces on the trailing side roof that were more vertically oriented with respect to the vehicle. The vertically oriented forces potentially create greater risk for severe neck or head injuries.

The mechanics of on-road, friction-induced rollovers were studied with the aid of a three-dimensional computer code specifically derived for this purpose. Motions of the wheels, vehicle body, occupant torso, and head were computed. Kane's method was utilized to develop the dynamic equations of motion in closed form. On-road rollover kinematics were compared to a dolly-type rollover at lesser initial speed, but generating a similar roll rotation rate. The simulated on-road rollover created a roof impact on the leading (driver's) side, while the dolly rollover simulation created a trailing-side roof impact. No head-to-roof contacts were predicted in either simulation. The first roof contact during the dolly-type roll generated greater neck loads in lateral bending than the on-road rollover. This work is considered to be the first step in developing a combined vehicle and occupant computational model for studying injury potential during rollovers.

Lateral head motions, torso motions, lateral neck bending angles, and electromyographic (EMG) activity patterns of five human volunteer passengers are compared to lateral motions of a Hybrid III ATD during right-left and left-right fishhook steering maneuvers leading to vehicular tip-up. While the ATD maintained relatively fixed lateral neck angles, live subjects leaned their heads slightly inward and actively utilized their neck musculature to stiffen their necks against the lateral inertial loads. Except for differences in neck lateral bending, the Hybrid III ATD reasonably reflects occupant kinematics during the pre-trip phase of on-road rollovers.