Human Occupant Motion in Rear-End Impacts: Effects of Incremental Increases in Velocity Change

Welcher, Judson; Szabo, Thomas J.; Voss, Daniel P.

doi:10.4271/2001-01-0899

Cited by 13 publications

(3 citation statements)

References 11 publications

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“…Of the remaining 34 studies, one was excluded as the authors reported barrier equivalent velocity (BEV) rather than delta V [ 18 ]. Among the 33 remaining studies there were data from 408 individual crash tests that could be abstracted for description and analysis [ 16 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. The number of unique test subjects could not be determined from the studies, as multiple studies were performed by the same authors who also included themselves as test subjects, and most papers described two or more crash tests per subject (making the likely number of unique subjects in the included studies between 100 and 200).…”

Section: Resultsmentioning

confidence: 99%

Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

Nolet

Nordhoff

Kristman

et al. 2021

IJERPH

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Injury claims associated with minimal damage rear impact traffic crashes are often defended using a “biomechanical approach,” in which the occupant forces of the crash are compared to the forces of activities of daily living (ADLs), resulting in the conclusion that the risk of injury from the crash is the same as for ADLs. The purpose of the present investigation is to evaluate the scientific validity of the central operating premise of the biomechanical approach to injury causation; that occupant acceleration is a scientifically valid proxy for injury risk. Data were abstracted, pooled, and compared from three categories of published literature: (1) volunteer rear impact crash testing studies, (2) ADL studies, and (3) observational studies of real-world rear impacts. We compared the occupant accelerations of minimal or no damage (i.e., 3 to 11 kph speed change or “delta V”) rear impact crash tests to the accelerations described in 6 of the most commonly reported ADLs in the reviewed studies. As a final step, the injury risk observed in real world crashes was compared to the results of the pooled crash test and ADL analyses, controlling for delta V. The results of the analyses indicated that average peak linear and angular acceleration forces observed at the head during rear impact crash tests were typically at least several times greater than average forces observed during ADLs. In contrast, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL. The results of our analysis indicate that the principle underlying the biomechanical injury causation approach, that occupant acceleration is a proxy for injury risk, is scientifically invalid. The biomechanical approach to injury causation in minimal damage crashes invariably results in the vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice.

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Section: Resultsmentioning

confidence: 99%

Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

Nolet

Nordhoff

Kristman

et al. 2021

IJERPH

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“…Twelve studies reported head acceleration experienced by the volunteers. 5 , 15 , 23 , 26 , 30 , 32 , 37 , 38 , 40 , 59 , 67 , 68 These studies provide 125 data points for head acceleration as a function of vehicle change in speed (Figure 6 ). These points were fit to a polynomial and power trendline, which produced similar accuracy.…”

Section: Resultsmentioning

confidence: 99%

A Comprehensive Review of Low-Speed Rear Impact Volunteer Studies and a Comparison to Real-World Outcomes

Cormier

Gwin

Reinhart

et al. 2018

Spine

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Study Design.This study combined all prior research involving human volunteers in low-speed rear-end impacts and performed a comparative analysis of real-world crashes using the National Automotive Sampling System – Crashworthiness Data System.Objective.The aim of this study was to assess the rates of neck pain between volunteer and real-world collisions as well as the likelihood of an injury beyond symptoms as a function of impact severity and occupant characteristics in real-world collisions.Summary of Background Data.A total of 51 human volunteer studies were identified that produced a dataset of 1984 volunteer impacts along with a separate dataset of 515,601 weighted occupants in real-world rear impacts.Methods.Operating-characteristic curves were created to assess the utility of the volunteer dataset in making predictions regarding the overall population. Change in speed or delta-V was used to model the likelihood of reporting symptoms in both real-world and volunteer exposures and more severe injuries using real-world data. Logistic regression models were created for the volunteer data and survey techniques were used to analyze the weighted sampling scheme with the National Automotive Sampling System database.Results.Symptom reporting rates were not different between males and females and were nearly identical between laboratory and real-world exposures. The minimal risk of injury predicted by real-world exposure is consistent with the statistical power of the large number of volunteer studies without any injury beyond the reporting of neck pain.Conclusion.This study shows that volunteer studies do not under-report symptoms and are sufficient in number to conclude that the risk of injury beyond neck strain under similar conditions is essentially zero. The real-world injury analyses demonstrate that rear impacts do not produce meaningful risks of cervical injury at impacts of similar and greater severity to those of the volunteer research. Future work concerning the mechanism of whiplash-related trauma should focus on impacts of severity greater than those in the current literature.Level of Evidence: 3

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“…Several experimental studies have analysed the role of the cervical muscles and have depicted the kinematics of head movement in simulated low-velocity rear-end impacts (1,3,5,8,(11)(12)(13)(14)(15)(16)(29)(30)(31)(32)(33). It has been reported that acceleration of the head increases with impact magnitude (1,8,20,29,34). The magnitude of angular head displacement is within physiological movement and does not support the Table 3.…”

Section: Discussionmentioning

confidence: 99%

Mandibular kinematics associated with simulated low‐velocity rear‐end impacts

Hernández¹,

Fyfe²,

Heo³

et al. 2006

J of Oral Rehabilitation

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Rear-end-impact motor vehicle accidents may result in cervical and temporomandibular-related pain complaints. Head kimematics in simulated low-impact rear-end impacts have been investigated but mandibular kinematics have not been described. Thirty healthy adult subjects underwent three impacts (4.5 m s(-2) expected, 10.0 m s(-2) unexpected, and 10.0 m s(-2) expected). Onset time and peak magnitude of angular head acceleration, angular mandibular acceleration and angular mandibular displacement were measured. Significant mandibular opening acceleration was not identified with rearward head rotation. The peak magnitude of mandibular closing angular acceleration approximately doubled with increased impact magnitude. No differences in peak angular mandibular acceleration regarding expectation were identified. Gender differences were detected in the fast unexpected impact. The peak time for the angular mandibular acceleration (mandibular closure) was approximately 84-120 ms later than peak rearward angular head acceleration for all impacts. Onset and peak times for angular mandibular acceleration (mandibular closure) were similar to the onset and peak times for forward head acceleration. There was also a positive correlation between the magnitude of the forward angular acceleration of the head and angular acceleration of the mandible for the slow (0.65, P = 0.015) and fast expected (0.844, P = 0.001) impacts. The average angular mandibular angular displacement (mandibular closure) was approximately 6 degrees . The hyperextension hypothesis regarding mechanism of temporomandibular joint injury in low-impact rear-end collisions cannot be supported.

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Human Occupant Motion in Rear-End Impacts: Effects of Incremental Increases in Velocity Change

Cited by 13 publications

References 11 publications

Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

A Comprehensive Review of Low-Speed Rear Impact Volunteer Studies and a Comparison to Real-World Outcomes

Mandibular kinematics associated with simulated low‐velocity rear‐end impacts

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