Computational prediction of head-ground impact kinematics in e-scooter falls
File(s)
Accepted version
Author(s)
Posirisuk, Pasinee
Baker, Claire
Ghajari, Mazdak
Type
Journal Article
Abstract
E-scooters are the fastest growing mode of micro-mobility with important environmental benefits. However, there are serious concerns about injuries caused by e-scooter accidents. Falls due to poor road surface conditions are a common cause of injury in e-scooter riders, and head injuries are one of the most common and concerning injuries in e-scooter falls. However, the head-ground impact biomechanics in e-scooter falls and its relationship with e-scooter speed and design, road surface conditions and wearing helmets remain poorly understood. To address some of these key questions, we predicted the head-ground impact force and velocity of e-scooter riders in different falls caused by potholes. We used multi-body dynamics approach to model a commercially available e-scooter and simulate 180 falls using human body models. We modelled different pothole sizes to test whether the pothole width and depth influences the onset of falls and head-ground impact speed and force. We also tested whether the e-scooter travelling speed has an influence on the head-ground impact force and velocity. The simulations were carried out with three human body models to ensure that the results of the study are inclusive of a wide range of rider sizes. For our 10inch diameter e-scooter wheels, we found a sudden increase in the occurrence of falls when the pothole depth was increased from 3cm (no falls) to 6cm (41 falls out of 60 cases). When the falls occurred, we found a head-ground impact force of 13.23.4kN, which is larger than skull fracture thresholds. The head-ground impact speed was 6.31.4m/s, which is nearly the same as the impact speed prescribed in bicycle helmet standards. All e-scooter falls resulted in oblique head impacts, with an impact angle of 6510 (measured from the ground). Decreasing the e-scooter speed reduced the head impact speed. For instance, reducing the e-scooter speed from 30km/h to 20km/h led to a 14% reduction in the mean impact speed and 12% reduction in the mean impact force, as predicted by the models. The models also showed that the median male riders were sustaining higher head-ground impact force and speed compared with the small female and large male riders. The findings of this study can assist authorities and e-scooter hiring companies to take more informed actions about road surface conditions and speed limits. These results can also help define representative impact test conditions for assessing the performance of helmets used by e-scooter riders in order to reduce head and brain injuries in e-scooter falls.
Date Issued
2022-03
Date Acceptance
2022-01-03
Citation
Accident Analysis and Prevention, 2022, 167, pp.1-11
ISSN
0001-4575
Publisher
Elsevier
Start Page
1
End Page
11
Journal / Book Title
Accident Analysis and Prevention
Volume
167
Copyright Statement
© 2022 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S0001457522000033?via%3Dihub
Subjects
Brain injury
E-scooter
Fall
Impact
Multi-body dynamics
Pothole
Accidental Falls
Accidents, Traffic
Biomechanical Phenomena
Craniocerebral Trauma
Female
Head Protective Devices
Humans
Male
Humans
Craniocerebral Trauma
Head Protective Devices
Accidental Falls
Accidents, Traffic
Female
Male
Biomechanical Phenomena
Logistics & Transportation
1117 Public Health and Health Services
1507 Transportation and Freight Services
1701 Psychology
Publication Status
Published
Article Number
106567
Date Publish Online
2022-01-13