Kinematics and shoulder belt engagement of children on belt-positioning boosters during evasive steering maneuvers

Baker, Gretchen; Stockman, Isabelle; Bohman, Katarina; Jakobsson, Lotta; Osvalder, Anna‐Lisa; Svensson, Mats Y.; Wimmerstedt, Maria

doi:10.1080/15389588.2017.1398401

Cited by 8 publications

(2 citation statements)

References 4 publications

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“…Several studies have investigated the influence of braking maneuvers on occupant kinematics ( Olafsd ottir et al 2013;Stockman et al 2013;Baker et al 2017). These previous studies were able to quantify the forward head and trunk displacement during the braking maneuver.…”

Section: Introductionmentioning

confidence: 99%

Effect of automated versus manual emergency braking on rear seat adult and pediatric occupant precrash motion

Graci

Douglas

Seacrist

et al. 2019

Traffic Injury Prevention

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Objective: Emergency braking can potentially generate precrash occupant motion that may influence the effectiveness of restraints in the subsequent crash, particularly for rear-seated occupants who may be less aware of the impending crash. With the advent of automated emergency braking (AEB), the mechanism by which braking is achieved is changing, potentially altering precrash occupant motion. Further, due to anatomical and biomechanical differences across ages, kinematic differences between AEB and manual emergency braking (MEB) may vary between child and adult occupants. Therefore, the objective of this study was to quantify differences in rear-seated adult and pediatric kinematics and muscle activity during AEB and MEB scenarios. Methods: Vehicle maneuvers were performed in a recent model year sedan traveling at 50 km/h. MEB (acceleration 1 g) was achieved by the driver pressing the brake pedal with maximum effort. AEB (acceleration 0.8 g) was triggered by the vehicle system. Inertial and Global Positioning System data were collected. Seventeen male participants aged 10-33 were restrained in the rear right passenger seat and experienced each maneuver twice. The subjects' kinematics were recorded with an 8-camera 3D motion capture system. Electromyography (EMG) recorded muscle activity. Head and trunk displacements, raw and normalized by seated height, and peak head and trunk velocity were compared across age and between maneuvers. Mean EMG was calculated to interpret kinematic findings. Results: Head and trunk displacement and peak velocity were greater in MEB than in AEB in both raw and normalized data (P .01). No effect of age was observed (P .21). Peak head and trunk velocities were greater in repetition 1 than in repetition 2 (P .006) in MEB but not in AEB. Sternocleidomastoid (SCM) mean EMG was greater in MEB compared to AEB, and muscle activity increased in repetition 2 in MEB. Conclusions: Across all ages, head and trunk excursions were greater in MEB than AEB, despite increased muscle activity in MEB. This observation may suggest an ineffective attempt to brace the head or a startle reflex. The increased excursion in MEB compared to AEB may be attributed to differences in the acceleration pulses between the 2 scenarios. These results suggest that AEB systems can use specific deceleration profiles that have potential to reduce occupant motion across diverse age groups compared to sudden maximum emergency braking applied manually.

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Section: Introductionmentioning

confidence: 99%

Effect of automated versus manual emergency braking on rear seat adult and pediatric occupant precrash motion

Graci

Douglas

Seacrist

et al. 2019

Traffic Injury Prevention

View full text Add to dashboard Cite

show abstract

“…The results of this study quantified pre-impact postures of children and seat-belt slippage as a result of vehicle swerving maneuvers for a variety of restraint systems. Similar testing methods were used by Baker et al [14] to quantify occupant kinematics and understand restraint interaction among pediatric subjects utilizing two different booster seat designs. Results of the abovementioned studies examined the influence of seat belt position on the potential for torso rollout from the shoulder belt induced by a maneuver characterized by lateral acceleration; however, the reverse acceleration pulse (movement into the shoulder belt) as might be experienced during an extended evasive swerving event was not explored.…”

Section: Introductionmentioning

confidence: 99%

Age Differences in Occupant Motion during Simulated In-Vehicle Swerving Maneuvers

Graci

Douglas

Seacrist

et al. 2020

IJERPH

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Background: With active safety and automated vehicle features becoming more available, unanticipated pre-crash vehicle maneuvers, such as evasive swerving, may become more common, and they may influence the resulting effectiveness of occupant restraints, and consequently may affect injury risks associated with crashes. Therefore, the objective of this study was to quantify the influence of age on key occupant kinematic, kinetic, and muscular responses during evasive swerving in on-road testing. Methods: Seat belt-restrained children (10–12 years old), teens (13–17 years old), and adults (21–33 years old) experienced two evasive swerving maneuvers in a recent model sedan on a test track. Kinematics, muscle activity, and seat belt load distribution were determined and analyzed. Results: Compared to teens and adults, children showed greater head and trunk motion (p < 0.03), but similar muscle activation in the into-the-belt direction of swerving. In the out–of-the-belt direction, children showed head and trunk motion more similar to teens and adults (p < 0.02), but with greater muscle activation. Conclusions: Children showed different neuromuscular control of head and trunk motion compared to older occupants. This study highlights differences in the relationship between kinematics and muscle activation across age groups, and provides new validation data for active human body models across the age range.

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The effect of reclined seatback angles on the motion of booster-seated children during lateral-oblique low-acceleration impacts

Graci

Burns

Griffith

et al. 2023

Accident Analysis & Prevention

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Kinematics and shoulder belt engagement of children on belt-positioning boosters during evasive steering maneuvers

Cited by 8 publications

References 4 publications

Effect of automated versus manual emergency braking on rear seat adult and pediatric occupant precrash motion

Effect of automated versus manual emergency braking on rear seat adult and pediatric occupant precrash motion

Age Differences in Occupant Motion during Simulated In-Vehicle Swerving Maneuvers

The effect of reclined seatback angles on the motion of booster-seated children during lateral-oblique low-acceleration impacts

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