Search Results

From the crash investigation files at the University of Michigan Transportation Research Institute (UMTRI), the crashes involving deployed airbags were reviewed. The total number of deployments is 898 of which 764 are frontal crashes with the principal direction of force (PDF) at 11-1 o’clock. Of the drivers in these frontal crashes 83% were using the belt restraint. Overall, seven of ten drivers have an AIS-0 or 1 level injury as the maximum or highest injury severity level (MAIS). Of the survivors, one in six had a moderate level injury (AIS-2) as their most significant injury and one in nine had an MAIS 3 or greater injury. Fatalities are rare. There is a difference between injury severity frequencies of belted vs. non-belted drivers. Three-quarters of the belted drivers had minor injuries compared to only half of those not belted. A difference was also noted at the AIS-2 level—belted vs. unbelted 14% vs. 23%.

At the University of Michigan Transportation Research Institute (UMTRI), 763 crashes involving steering wheel airbag deployments have been investigated in detail (as of 12/1/97). A subset of only frontal crashes, in which the steering wheel airbag deployed, and stature was known, was formed (636 drivers). In these crashes there were 201 “short” stature drivers, 165 cm or less in height (32% of all drivers). The vast majority of all drivers were lap-shoulder belted. Of these drivers, 69% sustained no injuries or an AIS-1 level injury. Of the shorter drivers there were 40 MAIS-2 level injuries and 15 who survived with an MAIS injury level of 3, 4, or 5. These higher level injuries were usually found in only one body area. Details of the injury locations and contacts are presented. Data on the taller drivers (435) were similarly tabulated. Of the taller drivers (> 168 cm), 74% had a MAIS-0 or 1 level injury.

In a review of 540 crashes in which the steering-wheel airbag deployed, 38% of the drivers sustained some level of upper extremity injury. The majority of these were AIS-1 injuries including abrasions, contusions and small lacerations. In 18 crashes the drivers sustained AIS-2 or-3 level upper extremity injuries, including fractures of the radius and/or ulna, or of the metacarpal bones, all related to airbag deployments. It was determined that six drivers sustained the fracture(s) directly from the deploying airbag or the airbag module cover. The remaining 12 drivers had fractures from the extremity being flung into interior vehicle structures, usually the instrument panel. Most drivers were taller than 170 cm and, of the 18 drivers, 10 were males.

To determine the frequency of facial injuries from steering-wheel airbag deployments, 540 consecutive steering-wheel airbag deployments, investigated by the University of Michigan Transportation Research Institute (UMTRI) personnel, were reviewed. About 1 in 3 drivers sustain an injury to the face. Injuries to the area surrounding the eye (periorbital) or to the eyeball (ocular) rarely occur. The frequencies of facial or ocular injuries are the same for belted and unbelted drivers. Drivers of short stature had a higher frequency of facial injury. Females sustained ocular injuries more frequently than males. Untethered airbags were not overly involved in drivers with an ocular injury. No specific make or model car were overly represented in the ocular injury cases.

This is an overview of air bag injuries, a review of the literature and descriptions of air bag related injuries to the various body areas. Some unusual injuries are also included. The cases presented are from the author's files and one from the Special Studies Division of NHTSA.

Using the CDC (SAE J224), a comparison of the NASS data and the UMTRI field accident files (UM series) indicates a similar distribution of offset frontal crashes. Offset frontal damage occurs in 56-61% of crashes, often involving more than one third of the front of the car. Lap-shoulder belted drivers sustain more AIS 2 or greater injuries when there is interior intrusion and occur more often when the offset damage is in front of the driver. However, this may well be due to the severity of the crash. European studies have no uniformity as to offset frontal collision descriptors are difficult to interpret, or to compare one to another.

From the authors' files, case examples of thoracolumbar injuries sustained by lap-shoulder belted front seat occupants, in frontal crashes, are presented. Additional cases were found in a review of the clinical literature. The biomechanical literature was reviewed, identifying laboratory studies on thoracolumbar spinal injuries. Suggested mechanisms in the production of these injuries in frontal type car crashes are postulated.

The effects of child safety seats have been well documented in the medical literature. Scattered throughout the medical literature are individual case reports of cervical injury to children restrained in child restraint systems. A review of the literature is provided identifying previous documented cases. The authors also provide new case details of children with cervical spine injury without head contact. An overview of the growth of the infant and specific details in the cervical spine that may contribute to significant cervical injury without head impact is presented.

Crash injury reduction via lap-shoulder belt use has been well documented. As any interior car component, lap-shoulder belts may be related to injury in certain crashes. Relatively unknown is the fact that cervical fractures or fracture-dislocations to restrained front seat occupants where, in the crash, no head contact was evidenced by both medical records and car inspection. An extensive review of the available world's literature on car crash injuries revealed more than 100 such cases. A review of the NASS 80-88 was also conducted, revealing more examples. Cases from the author's own files are also detailed.

NASS 80-88 passenger side impacts data were analyzed. Location of primary car damage using the CDC classification, the AIS for injury severity studies, and the interior contacts of the various body areas. Drivers alone, or with passengers were studied separately in both left and right side crashes. Direct impacts to the passenger compartment only are less frequent than to other CDC side zones. Driver interior contacts vary by body region but also by side impacted in the crash. The presence of an unrestrained front passenger appears to enhance driver injury level in left side crashes but the presence of a passenger, in right side crashes appears to moderate driver injury severity.

Frontal crashes (11-1 o'clock) were reviewed from the National Accident Severity Study file (NASS) for years 1980-87. Adult drivers and front right passengers, with lower extremity injuries of the pelvis, thigh, knee, leg or ankle/foot were reviewed. Analysis of age differences, injury contacts, and effectiveness of the 3-point restraint system were studied. Unrestrained drivers have a higher frequency of knee injuries than passengers, fewer leg injuries than passengers and both have the same frequency of ankle/foot injuries. Older unbelted drivers have more injuries to the pelvis, leg, and ankle/foot region than do young drivers. Passengers have more leg injuries. The instrument panel is the major contact for most of the lower extremity injuries. Lap/shoulder belts significantly reduce lower extremity injury frequency.

This paper presents an analysis of the NASS file (1980 - 1986). Cases were selected for near side impacts for drivers, i.e. left side of car, involving unrestrained adult drivers who were alone in the car, and who were not involved in any other collisions following the primary left side impact. Data analysis indicates that 11 % of the near side drivers had crush damage to only the passenger compartment, the ‘P’ zone, that the head, chest and abdomen predominate as the body areas of concern (AIS 3+ injuries), but that these injuries are sustained more often on structures other than the side interior.

The side impact, recently and currently the subject to of much debate, controversy and proposed NHTSA rule making, is a difficult type of crash to significantly reduce serious injuries and fatalites. Results from real-world crash investigations presents a confusing picture for the near-side passenger compartment crash. A direct relationship between the amount of crush and injury severity levels (MAIS) is not apparent. Exemplar cases of tow-a-way/injury crashes are presented at all AIS injury level of drivers in crashes with direct driver door crush damage.

Basilar skull fractures have previously been described as the result of cranial vault impacts. Such fractures resulting from impacts to the chin, face and/or orbital areas (non-cranial vault areas) have not been adequately documented. These types of fractures and the motor vehicle incidents in which the injuries were sustained will be described according to the type of crash and vehicles involved. Data on the tolerance levels of the basilar region of the skull are sparce at best. Case histories of non-cranial vault impacts, presented in a variety of crash types, document that facial impacts can be the sole cause of basilar skull fractures. A historical review of the basilar skull fracture literature is presented.

A review of the UM series and of NCSS, NASS, CPIR and FARS Files, as well as Michigan accident data files was undertaken, as well as a review of the NTSB “Rear Seat Study”. From these files rear seat occupany is approximately 10%, with children 6 years of age or less being 1/5th of these. About 50-60% of those in the sear seat are adults. Most of the injuries are at the lower AIS levels, with adults being more seriously injured. Of the more serious or fatal injuries, the head and face predominate by far, in all types of crashes involving unrestrainded rear seat occupants. When belts are worn there are few seriously or fatally injured rear occupants and of these, the abdominal area predominates. From available data, rear lap-belted passengers have the same MAIS level (or less) when compared to their front seat lap-shoulder belted counterparts.

Mechanisms of thoraco-abdominal trauma were investigated utilizing unembalmed, repressurized human cadavers subjected to frontal impact with a steering wheel assembly. The focus of this research program was on trauma to the soft-tissue organs surrounded by the thoracic cage, as well as on the kinematic response of the thoracic cage. The results are compared to other thoraco-abdominal research programs conducted at the University of Michigan Transportation Research Institute (UMTRI) during the last eight years.

An analysis of 211 automobiles having the ball-type E.A. device (GM cars - 1972–1980), involved in frontal crashes was made to determine the relationship between driver injury and the steering assembly. The majority of the drivers had MAIS of 0 or 1 (66%). The head was the most frequently injured body region with the lower extremities next in frequency. Of the unrestrained drivers studied, 43% had a thoracic injury, the majority of which were minor. There is no correlation between injury severity and steering rim or spoke deformation, or the amount of E.A. column compression. Specific terminology for certain aspects of the E.A. performance are suggested.

The purpose of this literature review was to determine areas of automotive injury information that may add to knowledge of injury type, frequency, severity, and cause. This paper is a review of the literature concentrating on the period between 1965 and present. Literature on car, van, or 1ight truck occupants has been reviewed for injury frequencies, types, and locations. Current experimental biomechanical articles are also included. A search was made for descriptions of injury frequency, restraint effectiveness, and the causes of specific injuries. Medical and engineering journals, texts, and books were reviewed. For convenience, this report is divided into sections by body region with an overview introduction on the anatomy of the specific region.

From field crash investigations conducted by the authors, a series of well documented crashes will be presented. In each, at least one occupant was wearing a lap-shoulder belt. Detailed injury reports will be presented along with photographs of car damage, occupant contact areas, and where possible, the estimated impact speeds.