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The research question investigated in this study is what are the key attributes of foot and ankle injury in the between-rail frontal crash? For the foot and ankle, what was the type of interior surface contacted and the type of resulting trauma? The method was to study with in-depth case reviews of NASS-CDS cases where a driver suffered an AIS=2 foot or ankle injury in between-rail crashes. Cases were limited to belted occupants in vehicles equipped with air bags. The reviews concentrated on coded and non-coded data, identifying especially those factors contributing to the injuries of the driver's foot/ankle. This study examines real-world crash data between the years 1997-2009 with a focus on frontal crashes involving 1997 and later model year vehicles. The raw data count for between-rail crashes was 732, corresponding to 227,305 weighted, tow-away crashes.

This study tracks vehicle design changes and frontal crash test performance in NHTSA's NCAP and IIHS consumer information tests since the mid-90s for the Honda Accord and Toyota Camry. The objective was to provide insights into how passenger cars have changed in response to frontal consumer information tests. The history of major design changes for each model was researched and documented. The occupant injury measures from both NHTSA and IIHS were computed and the ratings compiled for several generations of both vehicles. Changes in vehicle crash pulse and occupant injury measures from both NCAP and IIHS tests, and from Canadian low speed rigid barrier tests, when available, were used to assess driver frontal protection for various vehicle generations. Loading of the rigid barrier in NCAP tests was used to evaluate front end stiffness changes over the years.

The objective of the present study is to develop a better understanding of the reasons for airbag non-deployment in frontal crashes that produce serious injuries. The FARS data shows an increasing trend of fatal crashes involving airbag non-deployment with a higher fatality risk in recent model year vehicles. The reported number of fatalities in such crashes has increased by about 50 percent (from 500 per year to 780 per year) in the last five years. The percentage of fatalities with non-deployments has doubled in vehicles model year 1998 and later compared to earlier model years. Multiple impacts contribute to about 90 percent of the FARS frontal crashes with non-deployments. Crashes with a curb hit or guardrail impact as the first harmful event and a narrow impact crash with a tree or pole as a subsequent harmful event is the most frequent crash scenario in non-deployment related fatal crashes.

Vehicle stiffness is one of the three major factors in vehicle to vehicle compatibility in a frontal crash; the other two factors are vehicle mass and frontal geometry. Vehicle to vehicle compatibility in turn is an increasingly important topic due to the rapid change in the size and characteristics of the automotive fleet, particularly the increase of the percentage of trucks and SUVs. Due to the non-linear nature of the mechanics of vehicle structure, frontal stiffness is not a properly defined metric. This research is aimed at developing a well defined method to quantify frontal stiffness for vehicle-to-vehicle crash compatibility. The method to be developed should predict crash outcome and controlling the defined metric should improve the crash outcome. The criterion that is used to judge the aggressivity of a vehicle in this method is the amount of deformation caused to the vulnerable vehicles when crashed with the subject vehicle.

This paper uses NASS/CDS 1997-2004 to determine the crash factors that are most frequently associated with rollover fires. Rollover fire cases were analyzed by the NASS variables including vehicle type, fire origin, number of quarter-turns, and final rest position. Results show that the engine compartment was the most frequent location for the fire origin. The fuel tank was second in this category. The rest position on the roof was most frequently associated with fires in rollovers. However, the fire rate was not strongly influenced by the final rest position. High severity rollovers that involve more than eight quarter-turns or end-over-end motion had fire rates much higher than the average. An examination of 24 cases with major fires in recent model year vehicles found that impacts prior to the rollover occurred in more than half of the cases. All of the cases with leakage from the fuel tank had impacts prior to the rollover.

In the effort to understand and solve the frontal crash compatibility problem, one needs to use values of frontal stiffness. Various definitions of stiffness have been used in other studies based on measurements from NHTSA's 35mph frontal NCAP test. Those definitions varied from assuming a linear stiffness based on static crush to more refined ones that vary with time dependent crush. A major consideration in selecting a method is the amount of vehicle damage that occurs in an incompatible crash. To partially address this issue, a method was introduced based on the energy absorbed in a front to front crash at 25mph approach speed. Four alternative definitions of stiffness were studied.

Seventeen full-scale crash tests were conducted to evaluate technologies to reduce the vulnerability of sidesaddle tanks on full size GM pickup trucks manufactured during the period 1973-1987. These vehicles were alleged by the U.S. Department of Transportation to be vulnerable in severe side impacts. The test program was intended to evaluate designs that would reduce vulnerability in all crash directions. The best test results were obtained by two strategies that relocated the tank to less vulnerable locations. The two locations were: (1) in the cargo bed (bed mounted tank) and (2) underneath the bed, ahead of the rear axle and between the frame rails (center-mounted tank). Tanks mounted in these locations were subjected to a series of crash tests that simulated severe front, side, rear and rollover crashes. The crash environment for these tests was more severe than required by FMVSS 301 “Fuel System Integrity”.

In a side impact, the occupants on both the struck, or near side, of the vehicle and the occupants on the opposite, or far side, of the vehicle are at risk of injury. Since model year 1997, all passenger cars in the U.S. have been required to comply with FMVSS No. 214, a safety standard that mandates a minimum level of side crash protection for near side occupants. No such federal safety standard exists for far side occupants. The mechanism of far side injury is believed to be quite different than the injury mechanism for near side injury. Far side impact protection may require the development of different countermeasures than those which are effective for near side impact protection. This paper evaluates the risk of side crash injury for far side occupants as a basis for developing far side impact injury countermeasures. Based on the analysis of NASS/CDS 1993–2002, this study examines the injury outcome of over 4500 car, light truck, and van occupants subjected to far side impact.

The U.S. Department of Transportation-sponsored Crash Injury Research and Engineering Network (CIREN) program offers a reasonable look at the efficacy of second-generation air bags. This paper examines the data from the William Lehman Injury Research Center (WLIRC). The WLIRC data is a near census of crashes in the Miami-Dade region with occupants that appear to be severely injured. The percentage of deaths among trauma patients in the WLIRC data as a function of delta-V for first-generation air bags was higher than expected at lower delta-V's. There were nine driver fatalities at delta-V's of less than 20 mph (four involving short stature occupants, four with elderly occupants, and one due to significant intrusion and/or vehicle incompatibility). The data supported NHTSA's conclusion that first-generation air bags were too aggressive for occupants in close proximity to the deploying air bag and too aggressive for older persons.

Occupants exposed to far-side crashes are those seated on the side of the vehicle opposite the struck side. This study uses the NASS/CDS 1988–98 to determine distributions of serious injuries among restrained occupants exposed to far-side crashes and the sources of the injuries. Vehicle-to-vehicle crash tests were conducted to study dummy kinematics. The NASS/CDS indicated that the head accounted for 45% of the MAIS 4+ injuries in far-side collisions and the chest/abdomen accounted for 39%. The opposite-side interior was the most frequent contact associated with driver AIS 3+ injuries (26.9%). The safety belt was second, accounting for 20.8%. Vehicle-to-vehicle side impact tests with a 60 degree crash vector indicated that different safety belt designs resulted in different amounts of head excursion for the far side Hybrid III dummy. For all three point belt systems tested, the shoulder belt was ineffective in preventing large amounts of head excursion.

The URGENCY algorithm uses data from on-board crash recorders to assist in identifying crashes that are most likely to have time critical (compelling) injuries. The injury risks projected by using the NASS/CDS data are the basis for the URGENCY algorithm. This study applied the algorithm retrospectively to a population of injured occupants in the database from the University of Miami School of Medicine, William Lehman Injury Research Center (WLIRC). The population selected was adult occupants in frontal crashes that were protected by three-point belts plus an air bag. For the cases with greater than 50% predicted MAIS 3+ injury probability, 96% of the occupants in the study had MAIS 3+ injuries. For the cases with less than 10% predicted MAIS 3+ injury probability, 63% did not have MAIS 3+ injuries. Most of the of MAIS 3+ injuries not predicted involved injuries in multiple impact crashes, pole crashes or close-in occupants injured by air bag deployment.

Rollover crashes continue to be a serious and growing vehicle safety problem. Rollovers account for about 9% of passenger car crashes, and 26% of light truck crashes. Belt use in rollover crashes is about 51%, compared with 62% in planar crashes. Overall, 26.4% of the serious and fatal injuries to occupants exposed to crashes are in rollovers. Among this injured population 74.4% are unbelted. In light trucks, rollovers account for 47.4% of the serious or fatal injuries. Unbelted occupants suffer about 87% of the serious injuries and fatalities in light truck rollovers. The use of safety belts offers a dramatic reduction in injury rates for rollover crashes. For belted occupants of pickup trucks and utility vehicles in rollover crashes, the injury rates are about the same as for belted occupants of passenger cars in planar crashes. Improvementsts in safety belts offer large opportunities in safety.

Beginning in model year 1997, BMW introduced an innovative head protection system HPS called the Inflatable Tubular Structure (HPS). Tests indicate that the system dramatically reduces the severity of head impacts in side crashes. This investigation is an evaluation of casualty abatement benefits that are derived from applying injury measures based on the HPS test results to the population in US National Accident Sampling System (NASS/CDS). The results of component and vehicle crash tests are summarized. The procedures for estimating benefits are described along with the benefits in terms of injuries mitigated, maximum injuries to occupants mitigated, and fatalities prevented.

This paper investigates the effects of driver airbag inflation characteristics, airbag relative position, airbag to dummy relative velocity, and steering column characteristics using a finite element model of a vehicle, air bag, and Hybrid III 50% male dummy. Simulation is conducted in a static test environment using a validated finite element model. Several static simulation tests are performed where the air bag module's position is mounted in a rigid steering wheel and the vertical and horizontal distances are varied relative to the dummy. Three vertical alignments are used: one position corresponds to the head centered on module, another position corresponds to the neck centered on module, and the third position centers the chest on the module. Horizontal alignments vary from 0 mm to 50 mm to 100 mm. All of these tests are simulated using a typical pre-1998 type inflation curve (mass flow rate of gas entering the bag).

The National Highway Traffic Safety Administration (NHTSA) Special Crash Investigations database contains twelve completed cases of child fatalities in rearward facing child seats caused by deploying air bags. Three of these are now available for examination. An additional two cases were investigated by the William Lehman Injury Research Center at the University of Miami School of Medicine. These five cases are examined to evaluate crash environment, injury mechanisms, and circumstances which caused the child to be in front of the passenger side air bag Four of the cases were crashes with impacts with the side of other cars with crash severities less than 15 mph. The predominate injury mechanism was brain and skull injury from a blow transmitted to the rear of the head through the child seat back. In one case, the force to the head was transmitted downward, directly from air bag contact.

The William Lehman Injury Research Center has conducted multi-disciplinary investigations of one hundred seventy-eight crashes involving adult occupants protected by safety belts and air bags. In all cases, serious injuries were suspected. Nine cases involved serious heart injuries. These cases are not representative of crashes in general. However, when used in conjunction with National Accident Sampling System; Crashworthiness Data System (NASS/CDS) they provide insight into the most severe injuries suffered by restrained occupants in frontal crashes. Heart injuries are rare, but when they occur they are usually life threatening. NASS/CDS shows that heart injuries comprise about 0.2% of the injuries in frontal tow-away crashes. In the NHTSA file of Special Crash Investigations (SCI) of air bag cases, heart injuries are reported in 1% of the occupants over 15 years of age. Twenty-five percent of the fatally injured occupants had heart injuries, and 83% of those with heart injury died.

While the present air bag systems have been shown to be highly effective in high severity crashes, undesirable side effects have been reported in some low severity events. The inflation rate of the airbag during deployment has been cited as a factor which induces injuries. A rapid airbag deployment rate is advantageous to provide protection to occupants in severe crashes. On the other hand, airbag aggressivity associated with the high inflation rate can increase injuries in the lower severity crashes. The injury producing forces from the airbag increase as the occupant position becomes closer to the bag at the time of deployment. This paper describes the results of an analytical study to evaluate chest injury measures for reduced inflation rates of a Taurus type air bag in a variety of crash modes. A detailed nonlinear finite element model of an unfolding airbag and a 50th percentile male Hybrid III dummy are used in conjunction with a test buck to simulate frontal crashes.