Vehicle deceleration causes a backward inertial sensation.
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
4 sources for · 0 against
Four peer-reviewed and official records discuss vehicle deceleration and occupant acceleration responses. However, this counted support is partial and does not establish that vehicle deceleration causes a backward inertial sensation.
Abstract Objective Pre-pretensioner (PPT) seatbelts have been found to be effective in controlling vehicle occupants’ motion response to disturbances in optimally positioned occupants, but it is not clear how the PPT performs when the occupant is initially forward leaning. Previous work demonstrated that an acoustic startling pre-stimulus (ASPS) reduced trunk out-of-position in sled-simulated pre-crash maneuvers. Therefore, the aim of this study was to determine if coupling the PPT with the ASPS could reduce the needed magnitude and rate of belt tension of the PPT to reposition forward leaning occupants to their optimal position within the seatbelt. Methods Sixteen belt-restrained adult human volunteers (8 males and 8 females) restrained by a 3-point seatbelt on a vehicle seat in a forward leaning posture on a sled simulating pre-crash braking (approx. 1 g of maximum acceleration and 0.3 s duration) were exposed to sled perturbations with three belt configurations (low and high force PPT and no PPT), and two warning conditions (ASPS and no-ASPS). Head and trunk positions were extracted from the 3D motion-capture data. Repeated measure ANOVAs were used to understand the effect of sex, PPT, ASPS, and repetition on head and trunk positions. A survival analysis was also performed to understand the probability of the occupants moving rearward in the different conditions. Results The probability of the head and trunk to move rearward from the initial position was greater with the PPT than without the PPT (p = 0.01) and with the high force level than the low force level (p = 0.01). The interaction effect of ASPS x PPT showed that with no PPT, there was a greater probability for the head to move rearward from the initial position with ASPS than without ASPS (p < 0.03). The trunk shows a similar trend to the head, but the ASPS vs no-ASPS differences were not statistically significant (p = 0.06). No sex differences were found. Conclusions The PPT, particularly the high level, may be an effective countermeasure on its own to reduce trunk and head out-of-position in forward leaning postures in pre-crash scenarios. The ASPS reduced the occupants’ head forward position when the PPT was not available.
Mechanism of head and neck response to -Gx impact acceleration: a math modeling approach. Mathematical modeling has attained wider acceptance in recent years. In particular, the use of computer programs to simulate the dynamic response of a human in a crash situation has become an attractive alternative to full-scale experimental testing. This paper analyzes data on the dynamic response of the living human head and neck to -Gx impact acceleration, where the motion of the subject's head and neck in the midsagittal plane was monitored with inertial instrumentation and high-speed photography for confirmation. The Calspan "3D Computer Simulator of Motor Vehicle Crash Victims" was used to predict expected responses for the deceleration pulses employed. These estimates were compared to the fully instrumented human test runs. The standard 15-segment and 14-joint representation of the occupant was modified to include two sternoclavicular joints, increasing the articulation in the upper torso.
In dynamic driving simulators, the experience of operating a vehicle is reproduced by combining visual stimuli generated by graphical rendering with inertial stimuli generated by platform motion. Due to inherent limitations of the platform workspace, inertial stimulation is subject to shortcomings in the form of missing cues, false cues, and/or scaling errors, which negatively affect simulation fidelity. In the present study, we aim at quantifying the relative contribution of an active somatosensory stimulation to the perceived intensity of self-motion, relative to other sensory systems. Parti
n ΔV and the neck disability index (r = 0.46) and between ΔV and the QTF grade (r = 0.45) for any of the collision types. There was no ΔV threshold associated with acceptable sensitivity and specificity for the prognosis of a cervical spine injury. Conclusion
The results of this study indicate that ΔV is not a conclusive predictor for cervical spine injury in real-life motor vehicle accidents. This is of importance for surgeons involved in medicolegal expertise jobs as well as patients who suffer from whiplash-associated disorders (WADs) after motor vehicle accidents. Trial registration
The study complied with applicable German law and with the principles of the Helsinki Declaration and was approved by the institutional ethics commission. Background
Whiplash injuries remain a barely understood phenomenon. The economic damage caused by whiplash amounts to some 10 billion Euros a year in Europe [ 1 ] and 29 billion US Dollars a year in the USA [ 2 ]. As whiplash occurs as a result of motor vehicle accidents (MVAs), questions inevitably arise regarding who is liable for these costs.
Biomechanical considerations have been based on the assumption that damage to a given material only occurs when the energy that acts on this material is high enough. Thus, energy doses below a defined threshold have been considered harmless [ 3 , 4 ]. In this context, the parameter delta v (ΔV), which describes the velocity change of a motor vehicle during a collision with another vehicle, has become a widely accepted criterion for the energy that acts on the vehicle during a collision [ 5 ].
In numerous sled or car crash-test studies, volunteers were subjected to acceleration forces in order to define a threshold below which a cervical spine injury could be excluded [ 6 - 15 ]. The results of these studies are rather inconclusive and sometimes contradictory. Thus the scientific community has not yet reached consensus regarding the threshold value for cervical spine injuries after whiplash.
Everything we examined (4)
This check searched the claim as stated. It did not run a separate search for evidence against it.