Annual proceedings. Association for the Advancement of Automotive Medicine最新文献

This study describes the fatal crash experiences of older drivers. Data from two U.S. databases (NASS-CDS and FARS) were used. Several crash, vehicle, and occupant characteristics were compared across age groups, including vehicle type, crash direction (PDOF), severity (DeltaV), and injured body region. A sub-set of 97 fatally injured drivers was chosen for a detailed case study. The mean travel speed, DeltaV, and airbag deployment rate decreased significantly with age (p<0.001 unless noted). Mortality rate increased significantly with age. Older drivers killed were significantly more likely to die of a chest injury (47.3% vs. 24.0% in youngest group) and less likely to die of a head injury (22.0% vs. 47.1% in youngest group). Older drivers were more likely to die at a date after the crash date ("delayed death"), as were males (p=0.003). A 16-year-old driver had a 10.8%-12.0% probability of delayed death, while a 75-year-old had a 20.7%-22.7% probability. For those having a delayed death, the length of the delay increased significantly with age (2.9 days for age 16 vs. 7.9 for age 75). A subjective assessment of the case files indicated that frailty or a pre-existing health condition played a role in 4.3% of the younger drivers' deaths, but 50.0% of the older group.

Previous work identified a similar risk of injury for children seated on the struck side and center rear in side impact crashes in passenger cars. In order to further explain this finding, we investigated the effect of sharing the rear row with other occupants on injury risk and delineated differences in injury patterns among the seat positions. These analyses, conducted from a large child specific crash surveillance system, included: children 4-15 years old, rear seated, seat belt restrained, in a passenger car, and in a side impact crash. Injury risk was compared among each rear seat position stratified by the presence of other occupants on the rear row. Occupants are at an increased risk of injury if they sit alone on their row as compared to sitting with other occupants. Patterns of injuries distinct to each seat position were delineated.

The population of occupants in far-side crashes that are documented in the US National database (NASS/CDS) was studied. The annual number of front seat occupants with serious or fatal injuries in far-side planar and rollover crashes was 17,194. The crash environment that produces serious and fatal injuries to belted front seat occupants in planar far-side crashes was investigated in detail. It was found that both the change in velocity and extent of damage were important factors that relate to crash severity. The median severity for crashes with serious or fatal injuries was a lateral delta-V of 28 kph and an extent of damage of CDC 3.6. Vehicle-to-vehicle impacts were simulated by finite element models to determine the intrusion characteristics associated with the median crash condition. These simulations indicated that the side damage caused by the IIHS barrier was representative of the damage in crashes that produce serious injuries in far-side crashes. Occupant simulations of the IIHS barrier crash at 28 kph showed that existing dummies lack biofidelity in upper body motion. The analysis suggested test conditions for studying far-side countermeasures and supported earlier studies that showed the need for an improved dummy to evaluate safety performance in the far-side crash environment.

Previous work quantified a 59% reduction in injury risk for children in belt positioning booster seats (BPB) compared to those restrained in seat belts using a sample of crashes of all directions of impact. Experimental sled tests have highlighted the potential for extreme occupant excursion out of the BPB in side impact crash conditions. Using data from a large child specific crash surveillance system, the present study built upon these previous studies and quantified the relative effectiveness of BPB as compared to seat belts in reducing the risk of injury among 4-8 year olds in side impact crashes. Children in BPB were at a 58% reduction in risk of injury than those in seat belts in side impact crashes. This result varied by booster seat type: those in high back BPB were at a 70% reduction in injury risk while those in backless BPB did not experience a statistically significant reduction in injury risk compared to those in seat belts. This differential performance of the two types of BPB provides direction for future research into the design and performance of these restraints.

Alcohol dependence has been associated with behavioral risk factors and risk-taking tendencies. We investigated whether past alcohol dependent trauma center patients (n=42) retain the characteristics of current alcohol dependent patients (n=67) or whether they resemble patients without history of alcohol dependence (n=262). We found that past alcohol dependence patients retain some of the risk-taking tendencies (impulsivity and sensation seeking) and risk-taking behaviors (drinking and driving, riding with a drunk driver, binge drinking, speeding for the thrill) common to current alcohol dependent patients and they remain at a higher injury risk than the non alcohol dependent population.

The performance of rear facing child restraints in frontal crashes can be determined by controlling a) the child's kinematics and b) interactions with vehicle structures. Twelve sled tests were performed to analyze the effect of the location and structural properties of vehicle interior components. The role of restraint kinematics was studied by developing computational models which underwent idealized motions. Stiff structures originally offset from the restraint, but which contact the restraint late in the test, cause increased injury values. Attachment methods which reduce child restraint rotation and more rigidly couple the restraint to the vehicle result in the best safety performance.

National Automotive Sampling System (NASS) crash statistics were examined to understand injury patterns of belted occupants in rollover crashes and determine accuracy / completeness of selected NASS-coded variables. A comprehensive statistical study, followed by detailed engineering reviews of 278 NASS cases, is in progress. The primary objective is to understand rollover crash characteristics and their influence on rollover injury severity. Focus was on cases with "roof contact" as the injury source. Two groups- significant roof deformation with no injury, and significant injury with minimal roof deformation-are discussed, as are crash characteristics such as "arrested roll." Also, based on evaluation of existing NASS codes, recommendations are made to enhance NASS coding of rollover-related variables.

This study provided a consolidated evaluation of four separate demonstration projects aimed at reducing impaired driving through well-publicized enforcement. Each of the four demonstration projects used different enforcement approaches in an effort to reduce impaired driving crashes in the State. Georgia experienced a significant decrease in drinking-and-driving fatal crashes (14 percent using a ratio measure in a time series analysis). The program in Georgia (2800 checkpoints) saved an estimated 60 lives in the first year. While Louisiana experienced a raw decrease in the ratio of drinking drivers to nondrinking drivers in fatal crashes, when the control parishes and the comparison States were taken into consideration, the apparent decrease was neutralized. Although Pennsylvania's selected counties showed relative decreases across a variety of measures when compared to control counties and surrounding States, these decreases were not significant. In Tennessee, the ratio measure showed a significant decrease (-10.6 percent) compared to surrounding States with an estimated 43 lives saved in the first year. In summary, it appears that if States use a sobriety checkpoint model that includes (a) a statewide effort, (b) numerous sobriety checkpoints conducted each weekend throughout the year, (c) intensive publicity about the enforcement, and (d) properly trained law enforcement officials, significant decreases in impaired driving fatalities can be realized.

By incorporating material and geometrical properties into a model of the human thorax one can develop an injury criterion that is a function of stress and strain of the material and not a function of the global response of the thorax. Previous research on the mechanical properties of ribs has focused on a limited set of specific ribs. For this study a total of 52 rib specimens were removed from four cadaver subjects. Variation in peak moment by thoracic region was significant (p < 0.01) with average values of 2, 2.9 and 3.9 N-m for the anterior, lateral and posterior regions respectively. Two geometrical properties, radius of gyration and distance from the neutral axis, showed significant variation by region (p < 0.0001) as well as by rib level (p = < 0.01, 0.05). The results of this study can be used to update current models of the human thorax to account for the variation in strength and geometrical properties throughout the rib cage. Accounting for the variation in rib properties by region will improve injury predictive measures and, therefore, the ability to design systems to prevent thoracic injury.

A prospective study was conducted to determine if emergency vehicle driver risk behavior could be improved with an onboard computer-monitoring device, with real time auditory feedback. Data were collected over 18 months from 36 vehicles in a metropolitan EMS group, with >250 drivers. In >1.9 million recorded miles, performance improved from a baseline low of 0.018 miles between penalty counts to a high of 15.8 miles between counts. Seatbelt violations dropped from 13,500 to 4. There was a 20% saving in vehicle maintenance costs within 6 months. This technology demonstrated sustained cost savings in regards to vehicle maintenance as well as minimal retraining of drivers.