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Technical Paper

Abdominal Injuries in Frontal Crashes: Influence of Occupant Age and Seating Position

2018-04-03
2018-01-0535
Objective: This study investigated the incidence of abdominal injuries in frontal crashes by occupant age and seating position. It determined the risk for abdominal injury (AIS 2+) by organ and injury source. Methods: 1997-2015 NASS-CDS was analyzed to estimate the occurrence of abdominal injuries in non-ejected, belted occupants involved in frontal crashes. Vehicles were included with 1997+ model year (MY). The annual incidence and rate for different types of abdominal injury were estimated with standard errors. The sources for abdominal injury were determined. Results: 77.8% of occupants were drivers, 16.7% were right-front passengers and 5.4% were rear passengers. Rear passengers accounted for 77.1% of 8-11 year old (yo) and 17.2% of 12-17 yo group. The risk for moderate abdominal injury (MAIS 2 + abdo) was 0.30% ± 0.053% in drivers, 0.32% ± 0.086% in right-front passengers and 0.38% ± 0.063% in rear occupants.
Technical Paper

Assessment of the 50th Hybrid III Responses in Blunt Rear Impacts to the Torso

2021-04-06
2021-01-0919
Blunt impacts to the back of the torso can occur in vehicle crashes due to interaction with unrestrained occupants, or cargo in frontal crashes, or intrusion in rear crashes, for example. Six pendulum tests were conducted on the back of an instrumented 50th percentile male Hybrid III ATD (Anthropomorphic Test Device) to determine kinematic and biomechanical responses. The impact locations were centered with the top of a 15-cm diameter impactor at the T1 or at T6 level of the thoracic spine. The impact speed varied from 16 to 24 km/h. Two 24 km/h tests were conducted at the T1 level and showed repeatability of setup and ATD responses. The 16 and 24 km/h tests at T1 and T6 were compared. Results indicated greater head rotation, neck extension moments and neck shear forces at T1 level impacts. For example, lower neck extension was 2.6 times and 3.8 times greater at T1 versus T6 impacts at 16 and 24 km/h, respectively.
Journal Article

Basilar Skull Fractures by Crash Type and Injury Source

2011-04-12
2011-01-1126
Purpose: This study investigates NASS-CDS data on basilar skull fractures by crash type and injury source for various crash scenarios to understand the injury risks, injury mechanisms and contact sources. Methods: 1993-2008 NASS-CDS data was used to study basilar skull fractures in adult front occupants by crash type and injury source. Injury risks were determined using weighted data for occupants with known injury status in 1994+ model year vehicles. In-depth analysis was made of far-side occupants in side impacts and rear crashes using the NASS electronic cases. Results: Basilar skull fractures occur in 0.507 ± 0.059% of rollovers and 0.255 ± 0.025% of side impacts. The lowest risk is in rear impacts at 0.015 ± 0.007%. The most common contact source is the roof, side rails and header (39.0%) in rollovers, the B-pillar (25.8%) in side impacts and head restraint (55.3%) in rear crashes.
Technical Paper

Biofidelity and Injury Assessment in Eurosid I and Biosid

1995-11-01
952731
Side impact pendulum tests were conducted on Eurosid I and Biosid to assess the biofidelity of the thorax, abdomen and pelvis, and determine injury tolerance levels. Each body region was impacted at 4.5, 6.7, and 9.4 m/s using test conditions which duplicate cadaver impacts with a 15 cm flat-circular 23.4 kg rigid mass. The cadaver database establishes human response and injury risk assessment in side impact. Both dummies showed better biofidelity when compared to the lowest-speed cadaver response corridor. At higher speeds, peak force was substantially higher. The average peak contact force was 1.56 times greater in Biosid and 2.19 times greater in Eurosid 1 than the average cadaver response. The Eurosid I abdomen had the most dissimilar response and lacks biofidelity. Overall, Biosid has better biofidelity than Eurosid I with an average 21% lower peak load and a closer match to the duration of cadaver impact responses for the three body regions.
Technical Paper

Bounce-Overs: Fixed Object Impacts Followed by Rollovers

2004-03-08
2004-01-0334
In this study, U.S. crash data was analyzed to better understand bounce-over rollovers. Crash data was reviewed to evaluate the distribution of bounce-over crashes and injuries, initiation objects and impact locations. In passenger cars, bounce-over crashes account for 8.4% of rollovers but involve 36.2% of the seriously injured belted drivers. Most bounce-overs are initiated by contact with narrow objects such as a pole, tree or barrier, or large objects such as a ditch or embankment. Contact often occurs in the front of the vehicle. After contact, the vehicle yaws and rolls, and serious injuries are often sustained to the head. Based on field data, a laboratory test was developed to simulate a narrow object bounce-over. The test consists of towing a vehicle laterally on a fixture towards a stationary, angled barrier resting in gravel. The moving fixture is decelerated and the vehicle is released. The vehicle front impacts the edge of the barrier, simulating a narrow object impact.
Technical Paper

Case Study of Vehicle Maneuvers Leading to Rollovers: Need for a Vehicle Test Simulating Off-Road Excursions, Recovery and Handling

2003-03-03
2003-01-0169
Rollovers are an important vehicle safety issue. Various technologies have been developed to help prevent rollovers from occurring, but the evaluation of rollover resistance typically involves vehicle-handling tests that are conducted on flat road surfaces with a uniform or split coefficient of friction. The purpose of this study is to determine the precipitating events leading to rollovers by analyzing real-world rollover crashes. This is a first step in identifying and developing vehicle tests that are representative of the principal driving scenarios leading to rollovers. The sequence of events leading to rollovers was determined from 63 in-depth investigated cases in the NASS-CDS database from 1995-1999. The sequence was evaluated by vehicle maneuvers, vehicle stability, surface type, road and shoulder transition condition, posted and estimated speeds, vehicle type and driver injury severity.
Technical Paper

Crash Injury Prevention: A Case Study of Fatal Crashes of Lap-Shoulder Belted Occupants

1992-11-01
922523
A case study was conducted of 123 crashes involving 144 fatally injured lap-shoulder belted front-seat occupants. The crashes occurred throughout the United States in 1985-86 and involved 97 driver and 47 right-front passenger deaths in new vehicles. A judgment was made by consensus of a safety panel on the potential for saving the victim's life by the addition of safety technology. Supplemental airbags provided the greatest potential for improving the life-saving effectiveness of current lap-shoulder belts. Overall, airbags may have prevented 12% of the belted occupant fatalities and 27% of the deaths in frontal crashes. The benefit of supplemental airbags was greater for the right-front passenger, in part, because of more females and occupants over 60 years of age in that seating position. A majority (68%) of the belted fatalities were judged unpreventable by reasonable restraint or vehicle modifications.
Technical Paper

Design of a Modified Chest for EUROSID Providing Biofidelity and Injury Assessment

1989-02-01
890881
The purpose of this study was to replace the axial deforming elements in the current EUROSID dummy with spring steel ribs and attached damping material to provide improved biofidelity in the lateral chest impact response. This report provides a description of the design, construction, and evaluation of the modified EUROSID chest for injury assessment in side impact crashes. Three spring steel ribs were designed to provide stiffness and deflections of 120 mm when attached to the block on the spine of the EUROSID dummy. Damping material was epoxied to the ribs and the system provided biofidelity in the lateral impact response for blunt impact loading at 4.3 m/s and 6.7 m/s. The new design provides significantly reduced inertia of the near side rib cage, elastic and viscous properties that are representative of the lateral human response and the ability to measure the deflection response of the rib cage for injury assessment with the Viscous response.
Technical Paper

Dual-Recliner ABTS Seats in Severe Rear Sled Testswith the 5th, 50th and 95th Hybrid III

2021-04-06
2021-01-0917
Seat strength has increased over the past four decades which includes a transition to dual recliners. There are seat collision performance issues with stiff ABTS and very strong seats in rear impacts with different occupant sizes, seating positions and physical conditions. In this study, eight rear sled tests were conducted in four series: 1) ABTS in a 56 km/h (35 mph) test with a 50th Hybrid III ATD at MGA, 2) dual-recliner ABTS and F-150 in a 56 km/h (35 mph) test with a 5th female Hybrid III ATD at Ford, 3) dual-recliner ABTS in a 48 km/h (30 mph) test with a 95th Hybrid III ATD leaning inboard at CAPE and 4) dual-recliner ABTS and Escape in 40 km/h (25 mph) in-position and out-of-position tests with a 50th Hybrid III ATD at Ford. The sled tests showed that single-recliner ABTS seats twist in severe rear impacts with the pivot side deformed more rearward than the stanchion side.
Technical Paper

Effect of ATD Size, Vehicle Interior and Restraint Misuse on Second-Row Occupant Kinematics in Frontal Sled Tests

2021-04-06
2021-01-0914
Interest in rear-seat occupant safety has increased in recent years. Information relevant to rear-seat occupant interior space and kinematics are needed to evaluate injury risks in real-world accidents. This study was conducted to first assess the effect of size and restraint conditions, including belt misuse, on second-row occupant kinematics and to then document key clearance measurements for an Anthropomorphic Test Device (ATD) seated in the second row in modern vehicles from model years 2015-2020. Twenty-two tests were performed with non-instrumented ATDs; three with a 5th percentile female Hybrid III, 10 tests with a 10-year-old Hybrid III, and 9 tests with a 6-year-old Hybrid III. Test conditions included two sled bucks (mid-size car and sport utility vehicle (SUV)), two test speeds (56 and 64 km/h), and various restraint configurations (properly restrained and improperly restrained configurations). Head and knee trajectories were assessed.
Technical Paper

Effect of Occupant Weight and Initial Position in Low-to-High Speed Rear Sled Tests with Older and Modern Seats

2021-04-06
2021-01-0918
The average body weight of the US population has increased over time. This study investigates the effect of increasing weight on seat and occupant responses in 15-18 km/h and 42 km/h rear sled tests. The effect of initial occupant posture is also discussed. Seven tests were conducted with lap-shoulder belted ATDs (anthropometric test device) placed on older and modern driver seats. Four tests were conducted with a 50th percentile male Hybrid III, two with 95th percentile male Hybrid III and one with a BioRID. The ATDs were ballasted to represent a Class I or II obese occupant in three tests. The tests were matched by seat model and sled velocity. The effect of occupant weight was assessed in three matches. The results indicated an increase in seatback deflection with increasing occupant weight.
Technical Paper

Effectiveness of High-Retention Seats in Preventing Fatality: Initial Results and Trends

2003-03-03
2003-01-1351
In 1995, new seat specifications were adopted by GM to provide high retention and improve occupant safety in rear crashes. With more than five years of phase-in of high retention (HR) seats, an analysis of FARS was undertaken to determine the initial field performance of HR seats in preventing fatalities. The 1991-2000 FARS was sorted for fatal rear-impacted vehicles. Using a VIN decoder, GM vehicles with HR front seats were sorted from those with baseline (pre-HR) seats. The fatal rear-impacted vehicle crashes were subdivided into several groups for analysis: 1) single-vehicle rear impacts, 2) two-vehicle rear crashes involving light striking vehicles, and 3) two-vehicle crashes involving heavy trucks and tractor-trailers, and multi-vehicle (3+) rear crashes.
Technical Paper

Evaluation of Armrest Loading in Side Impacts

1991-10-01
912899
Door armrests of different crush properties and placement were evaluated in a series of side impact sled tests. Three armrest designs were fabricated with an identical shape but different crush force. The crush properties covered a range in occupant protection systems based on knowledge of human tolerance in side impacts. With BioSID, the softest armrest produced the lowest compression and Viscous responses, and the probability of AIS 4+ injury was below 1%. The compression-based responses increased significantly in tests with armrests of a higher crush force. The profile of the stiffer armrests clearly protruded into the dummy, and the probability of serious injury was 86%-100% based on compression. With SID, the lowest TTI(d) was with the intermediate stiffness armrest. The SID dummy and TTI(d) criterion indicated a 4%-8% probability of AIS 4+ injury for all test conditions and armrest designs.
Technical Paper

Evaluation of Laminated Side Window Glazing Coding and Rollover Ejection Mitigation Performance Using NASS-CDS

2020-04-14
2020-01-1216
Occupant ejection has been identified as a safety problem for decades, particularly in rollover crashes. While field accident studies have repeatedly demonstrated the effectiveness of seat belts in mitigating rollover ejection and injuries, the use of laminated glass in side window positions has been suggested as a means to mitigate occupant ejection. Limited data is available on the field performance of laminated glass in preventing ejection. This study utilized 1997-2015 NASS-CDS data to investigate the reliability of the glazing coding variables in the database and determine if any conclusions can be drawn regarding the effect of different side window glazing types on occupant ejection. An initial query was run for 1997-2016 model year vehicles involved in side impacts to evaluate glazing coding within NASS-CDS.
Technical Paper

Evaluation of the Benefit of Energy-Absorbing Material in Side Impact Protection: Part II

1987-11-01
872213
This paper refines the methodology presented in the companion paper linking reductions in biomechanical responses due to force-limiting material to projections of injury-mitigation in real-world side impact crashes. The revised approach was used to evaluate the potential injury reducing benefit for the chest and abdomen with either constant crush force or constant stiffness, crushable material in the side door and armrest. Using a simulation of the human impact response, a range in crush force or stiffness was determined which reduced the viscous response from that obtained with a rigid impact. NCSS field accident data for car-to-car side impacts provided information on the occupant exposure and injury as a function of the change in velocity (ΔV) of the struck vehicle. Since the velocity of the side door at contact with the occupant's chest is similar to the ΔV of the struck vehicle, the chest impact velocity in the simulation was assumed equal to the observed ΔV in the NCSS data.
Technical Paper

Evaluation of the Benefit of Energy-Absorbing Material in Side impact Protection: Part I

1987-11-01
872212
This paper presents a methodology to link reductions in biomechanical responses due to force-limiting material to projections of injury mitigation in real-world side impact crashes, and to use this approach to evaluate the potential injury reducing benefit for the chest and abdomen of constant crush force material in the side door and armrest. Using a simulation of the human impact response, a range in crush force was determined which effectively reduced a peak biomechanical response from that obtained with a rigid impact. The range in constant crush force depended on the velocity of impact. The higher the velocity of impact, the higher the level of crush force to achieve a reduction in the peak response. NCSS field accident data for car-to-car side impacts provided information on the occupant exposure and injury as a function of the change in velocity (ΔV) of the struck vehicle.
Technical Paper

Evaluation of the SID Dummy and TTI Injury Criterion for Side impact Testing

1987-11-01
872208
The NHTSA's side impact dummy (SID) was evaluated against what is known of the side impact response of the human chest and responses were compared with data on Hybrid III frontal and EURQSID side impact characteristics. The SID dummy lacks a human-like chest deflection response which is crucial to the injury indicating capability of a dummy, it has a 9.8 kg near-side rib mass which is approximately an order of magnitude greater than that of the human, and it develops impact forces that are nearly three times higher than the recommended human chest response. It possesses characteristics primarily of an inertial device. The thoracic trauma index (TTI) was evaluated as an indicator of side impact injury risk, and design trends and optimized padding characteristics identified with the SID and TTI were compared with those from the Hybrid III dummy and viscous or compression injury criteria.
Technical Paper

Fatal Crashes of Female Drivers Wearing Safety Belts

1996-02-01
960459
Fatal crash circumstances for 48 belted female drivers were studied in-depth and compared to those of 83 belted male drivers in a similar population of vehicles. Women had a higher incidence of crashes on slippery roads, during lane changes and passing maneuvers than men who had a higher rate of aggressive driving and speed related crashes (χ2 = 10.47, p < 0.001). Driver-side damage was significantly more frequent in female than male crashes (χ2 = 5.74, p < 0.025) and women had a higher fraction of side impacts (45.9% v 31.4%) and crashes during daylight (87.0% v 72.3%, χ2 = 3.65, p < 0.05) than men. Women also had a higher fraction of potentially avoidable crashes than men (57.5% v 39.0%) and a lower involvement related to aggressive driving (10.6% v 25.6%). These differences were statistically significant (χ2 = 5.41, p < 0.025).
Technical Paper

Fatalities by Seating Position and Principal Direction of Force (PDOF) for 1st, 2nd and 3rd Row Occupants

2008-05-12
2008-01-1850
Purpose: A better understanding of rear occupant fatality risks is needed to guide the development of safety improvements for 2nd and 3rd row occupants. This study investigates fatal accidents of 1st, 2nd and 3rd row occupants by principal direction of force (PDOF), irrespective of restraint use. It determined the number of fatalities, exposure and fatality risk. Methods: 1996-2005 FARS was analyzed for occupant fatalities by seating position (1st, 2nd and 3rd row) and principal direction of force (1-12 o'clock PDOF, rollover and other/unknown). Light vehicles were included with model year 1990+. 1996-2005 NASS-CDS was similarly analyzed for occupant exposure. Fatality risk was defined as the number of fatalities in FARS for a given category divided by the exposure from NASS-CDS. Results: Ten percent (9.6%) of fatalities were to 2nd row occupants in FARS. About 2,080 deaths occur to 2nd row occupants annually. 38.4% died in rollovers and 26.8% in frontal crashes.
Technical Paper

Field Accident Data Analysis of 2nd Row Children and Individual Case Reviews

2008-05-12
2008-01-1851
Child safety is an important issue. The objective of this study was to analyze field accident data for 0-7 year old children in the 2nd row by vehicle and crash type, irrespective of restraint use. The data was obtained from NASS-CDS for calendar years 1991-2005. Accidents were selected based on 2nd row occupancy in towaway light vehicles with model year 1990 or newer. Side impacts caused 30.9% of serious-to-fatal injury (MAIS 3+F) to 2nd row children followed by frontal impacts (29.8%), rollovers (24.4%) and rear crashes (15.0%). The highest risk for MAIS 3+F was in rollovers (2.8 ± 0.7%) followed by rear (1.4 ± 0.4%), side (1.0 ± 0.2%) and frontal (0.46 ± 0.10%) crashes. The differences are statistically significant (p <0.01). Individual rear and frontal impact cases were also reviewed to better understand injury mechanisms of children in the 2nd row. The cases were obtained from the 1997-2005 NASS-CDS electronic database.
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