Search Results

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.

In this study, the occupant containment characteristics of automotive laminated safety glass in side window applications was evaluated through two full-scale, full-vehicle dolly rollover crash tests. The dolly rollover crash tests were performed on sport utility vehicles equipped with heat-strengthened laminated safety glass in the side windows in order to: (1) evaluate the capacity of laminated side window safety glass to contain unrestrained occupants during rollover, (2) analyze the kinematics associated with unrestrained occupants during glazing interaction and ejection, and (3) to identify laminated side window safety glass failure modes. Dolly rollovers were performed on a 1998 Ford Expedition and a 2004 Volvo XC90 at a nominal speed of 43 mph, with unbelted Hybrid II Anthropomorphic Test Devices (ATDs) positioned in the outboard seating positions.

This study was conducted to assess the occupant restraint use and injury risks by seating position. The results were used to discuss the merit of selected warning systems. The 1989-2015 NASS-CDS and 2017-2021 CISS data were analyzed for light vehicles in all, frontal and rear tow-away crashes. The differences in serious injury risk (MAIS 3+F) were determined for front and rear seating positions, including the right, middle and left second-row seats. Occupancy and restraint use were determined by model year groups. Occupancy relative to the driver was 27% in the right-front (RF) and 17% in the second row in all crashes. About 39% of second-row passengers were in the left seat, 15% in the center seat and 47% in the right seat. Restraint use was lower in the second row compared to front seats. It was 43% in the right-front and 32% in the second-row seats in all crashes involving serious injury. Restraint use increased with model year groups.

Objective: Sled test video and data were independently analyzed to assess the validity of statements and conclusions reported in Bidez et al. SAE paper 2005-01-1708 [7]. Method: An independent review and analysis of the test data and video was conducted for 9 sled tests at 35 km/h (21.5 mph). The 5th female Hybrid III was lap-shoulder belted in the 2nd or 3rd row seat of a SUV buck. For one series, the angle was varied from 0, 15, 30, 45 and 60 deg PDOF. The second series involved shoulder belt pretensioning and other belt modifications. Results: Bidez et al. [7] claimed “The lap belts moved up and over the pelvis of the small female dummy for all impact angles tested.” We found that there was no submarining in any of the tests with the production lap-shoulder belts. Bidez et al. [7] claimed “H3-5F dummies began to roll out of their shoulder belt at… 30 degrees. Complete loss of torso support was seen at 45 degrees without significant kinetic energy dissipation.”

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.

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.

Spine degeneration can lower injury tolerance and influence injury outcomes in vehicle crashes. To date, limited information exists on the effect of age and sex on thoracic spine 3-dimensional geometry. The purpose of this study is to quantify thoracic spinal column and canal geometry using selected geometrical measurement from a large sample of CT scans. More than 33,488 scans were obtained from the International Center for Automotive Medicine database at the University of Michigan under Institutional Review Board approval (HUM00041441). The sample consisted of CT scans obtained from 31,537 adult and 1,951 pediatric patients between the ages of 0 to 99 years old. Each scan was processed semi-automatically using custom algorithms written in MATLAB (The Math Works, Natick, MA). Five geometrical measurements were collected including: 1) maximum spinal curvature depth (D), 2) T1-to-T12 vertical height (H), 3) Kyphosis Index (KI), 4) kyphosis angle, and 5) spinal canal radius.

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.

The legends of Table 6 and Table 7, found on pages 924 and 925, did not properly reference multiple characters used within the tables.

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.

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.

Anthropomorphic test dummies (ATDs) have been validated for the analysis of various types of automobile collisions through pendulum, impact, and sled testing. However, analysis of the fidelity of ATDs in rollover collisions has focused primarily on the behavior of the ATD head and neck in axial compression. Only limited work has been performed to evaluate the behavior of different surrogate models for the analysis of occupant motion during rollover. Recently, Moffatt et al. examined head excursions for near- and far-side occupants using a laboratory-based rollover fixture, which rotated the vehicle about a fixed, longitudinal axis. The responses of both Hybrid III ATD and human volunteers were measured. These experimental datasets were used in the present study to evaluate MADYMO ATD and human facet computational models of occupant motion during the airborne phase of rollover.

By their nature as chaotic, high-energy events, rollovers pose a high risk of injury to unrestrained occupants, in particular through exposure to projected perimeter contact and ejection. While seat belts have long been accepted as a highly effective means of retaining and restraining occupants in rollover crashes, it has been suggested that technologies such as laminated safety glazing or rollover-activated side curtain airbags (RSCAs) could alternatively provide effective occupant containment. In this study, a full-scale dolly rollover crash test was performed to assess the occupant containment capability of laminated side glazing and RSCAs in a high-severity rollover event. This allowed for the analysis of unrestrained occupant kinematics during interaction with laminated side glazing and RSCAs and evaluation of failure modes and limitations of laminated glazing and RSCAs as they relate to partial and complete ejection of unrestrained occupants.

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.

Airbag and seat belt pretensioner deployment characteristics depend on multiple factors, such as the magnitude, direction, and rate of vehicle deceleration as detected by vehicle crash sensors and evaluated by vehicle-specific algorithms. Frontal airbag and pretensioner deployments are likely to be commanded during frontal crash events with high initial vehicle deceleration typically associated with high vehicle change in velocity (delta-V). However, within a range of moderate changes in vehicle speeds, referred to as the “gray zone,” a vehicle-specific algorithm may or may not command deployment depending on crash pulse parameters and occupant sensing, among other items. Publicly available testing in the moderate-speed range is lacking and would be useful to evaluate the effects of airbag and pretensioner deployment on occupant kinematics and loading.

Field data was analyzed on second-row children in front, side and rear impacts to study fatality trends by model year (MY) and calendar year (CY) with 1980-2020 MY vehicles. The different MY and CY perspectives show changes in rates that are useful for setting priorities for second-row child safety in rear impacts. 1990 to 2019 FARS was queried to assess the number of fatally injured and non-ejected second-row children (0-15 years old) in crashes without fires. The children included outboard occupants seated behind an occupied front seat and center occupants. The data was analyzed for rear, front and side impacts to assess crash frequency. 1990-2015 POLK was queried to assess exposure of registered vehicles and estimate a fatality rate. The FARS and POLK data were sub-grouped by MY of the vehicle and CY of the crash. There were 2.8-times more fatally injured children in frontal crashes than in the rear crashes. The ratio of frontal and rear crashes varied with CY sub-groups.

Since more occupants are using rear seats of vehicles, a better understanding of priorities for rear occupant protection is needed as future safety initiatives are considered. A two-part study was conducted on occupant injuries in rear seating positions. In Part I, adult and teenage occupants ≥13 years of age are investigated. In Part II, children aged 4-12 years old and toddlers and infants aged 0-3 are studied separately because of the use of infant and child seats and boosters involve different injury mechanisms and tolerances. The objectives of this study on adult and teenager, rear-seated occupants (≥13 years old) are to: 1) review accident data, 2) identify the distribution of rear occupants, and 3) analyze injury risks in various crash modes, including rollovers, frontal, side and rear impacts. Three databases were investigated: NASS-CDS, GES and FARS.

Child safety continues to be an important issue in automotive safety for many reasons, including reported cases of serious injury from airbag deployments. As a result of extensive public education campaigns, most children are now placed in rear seats of vehicles. Accordingly, a more precise understanding of rear-seat occupant protection is developing as the second and third rows have become the primary seating area for children in SUVs, vans and passenger cars. The objective of this study was to review field crash and injury data from rear seats, identify the distribution of children and infants in rear seats, and analyze injury risks in various crash modes. The database used was the 1991-1999 NASS-CDS. When looking at crash configurations for 1st and 2nd row children, rollover crashes involved the highest incidence of MAIS 3+ injury, followed by frontal and side impacts. Lap-shoulder belt usage was similar for 1st and 2nd row children.

Seats have become stronger over the past two decades and remain more upright in rear impacts. While head restraints are higher and more forward providing support for the head and neck, serious-to-fatal injuries to the thoracic and cervical spine have been seen in occupants with spinal disorders, such as DISH (diffuse idiopathic skeletal hyperostosis), ankylosis, spondylosis and/or osteophytes that ossify the joints in the spine. This case study addresses the influence of spinal disorders on fracture-dislocation and spinal cord injury in rear impacts with relatively upright seats. Nineteen field accidents were investigated where serious-to-fatal injuries of the thoracic and cervical spine occurred with the seat remaining upright or slightly reclined. The occupants were lap-shoulder belted, some with belt pretensioning and cinching latch plate.

This study assesses the exposure distribution and injury rate (MAIS 4+F) to front-outboard non-ejected occupants by crash severity, belt use and head restraint type and damage in rear impacts using 1997-2015 NASS-CDS data. Rear crashes with a delta V <24 km/h (15 mph) accounted for 71% of all exposed occupants. The rate of MAIS 4+F increased with delta V and was higher for unbelted than belted occupants with a rate of 11.7% ± 5.2% and 6.0% ± 1.5% respectively in 48+ km/h (30 mph) delta V. Approximately 12% of front-outboard occupants were in seats equipped with an integral head restraint and 86% were with an adjustable head restraint, irrespective of crash severity. The overall injury rate was 0.14% ± 0.05% and 0.22% ± 0.06%, respectively. It was higher in cases where the head restraint was listed as “damaged”. Thirteen cases involving a lap-shoulder belted occupant in a front-outboard seat in which “damage” to the adjustable head restraint was identified.