The price of personal mobility: burden of injury and mortality from personal mobility devices in Singapore - a nationwide cohort study

Introduction: Personal mobility devices (PMDs), such as electronic scooters or motorised bicycles, are efficient modes of transportation. Their recent popularity has also resulted in an increase in PMD-related injuries. We aimed to characterise and compare the nature of injuries sustained by PMD users and bicycle riders. Methods: This retrospective study compared injury patterns among PMD and bicycle users. 140 patients were admitted between November 2013 and September 2018. Parameters studied included patients’ demographics (e.g. age, gender and body mass index), type of PMD, nature of injury, surgical intervention required, duration of hospitalisation and time off work. Results: Of 140 patients, 46 (32.9%) patients required treatment at the department of orthopaedic surgery. 19 patients were PMD users while 27 were bicycle riders. 16 (84.2%) patients with PMD-related injuries were men. PMD users were significantly younger (mean age 45 ± 15 years) when compared to bicycle riders (mean age 56 ±17 years; p < 0.05). A quarter (n = 5, 26.3%) of PMD users sustained open fractures and over half (n = 10, 52.6%) required surgical intervention. Among 27 bicycle users, 7.4% (n = 2) of patients sustained open fractures and 70.4% (n = 19) required surgical intervention. Both groups had comparable inpatient stay duration and time off work. Conclusion: PMD-related orthopaedic traumas are high-energy injuries, with higher rates of open fractures, when compared to bicycle injuries. In addition, PMD users are significantly younger and of economically viable age. Prolonged hospitalisation and time off work have socioeconomic implications. Caution should be exercised when using PMDs.

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Numerical Investigation of Optimal Air Flowrate for Cooling 600 W Brushless Direct-Current Motor

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4048755 ◽

2021 ◽

Vol 13 (4) ◽

Author(s):

Hwabhin Kwon ◽

Heesung Park

Keyword(s):

Direct Current ◽

Air Flow ◽

Three Dimensional ◽

Energy Utilization ◽

Maximum Efficiency ◽

Heat Sources ◽

Additional Increase ◽

Personal Mobility ◽

Mobility Devices ◽

Flow Through

Abstract Personal mobility devices have drawn growing attention to relieve the congestion of traffic and air pollution. The efficiency of electric motors is significant in terms of energy utilization, driving range, and lifetime of the devices. In this study, a brushless direct-current (BLDC) motor is numerically investigated to maximize the system efficiency. The inevitable energy losses in the motor are evaluated using heat sources generated in the motor components. The resulting copper and iron losses generate heat and decrease the motor efficiency. With these, the developed three-dimensional numerical model accurately predicts the temperature variations of the motor components in accordance with the experimental results. Numerical simulations are conducted by supplying air flow at a rate of 0 to 40 l/min. The results show that the decreased temperature at copper windings improves the efficiency of the motor as more air flowrate is supplied. Nonetheless, after the temperature at the copper windings reaches 42.5 °C at an air flow of 30 l/min, the temperature remains constant despite additional increase in the air flow. Through a comparison between the improved electrical work by cooling and the consumed energy to supply the air flowrate, the maximum efficiency of the air-cooled BLDC is found to be 86.3% with an optimal air flowrate of 30 l/min.

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Effects of Human Factors on Public Use of Standing-Type Personal Mobility Vehicle

Journal of Advanced Transportation ◽

10.1155/2020/8876040 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Naohisa Hashimoto ◽

Kohji Tomita ◽

Osamu Matsumoto ◽

Ali Boyali

Keyword(s):

Future Development ◽

Real World ◽

Public Transport ◽

Urban Areas ◽

Traffic Accidents ◽

Transport Systems ◽

Personal Mobility ◽

Mobility Devices ◽

Personal Mobility Vehicle ◽

Mobility Device

To significantly reduce the occurrence of severe traffic accidents, reducing the number of vehicles in urban areas should be considered. Personal mobility is essential for realizing this reduction, which requires consideration of the last-/first-mile problem. The overall objective of our research is to solve this problem using standing-type personal mobility vehicles as transportation devices; however, to evaluate the feasibility of such vehicles as future mobility devices, it is necessary to evaluate their operation under real-world conditions. Therefore, in this study, experimental and survey data relating to the velocity, stability, safety, and comfort of a standing-type personal mobility device are obtained to evaluate its performance in three different scenarios. The results show that the personal mobility vehicle is socially well received and can be safely operated on sidewalks, irrespective of the gender or age of the driver; moreover, the results suggest that subjects who routinely use a bicycle are adept at avoiding and absorbing the impacts of small holes and bumps, thereby yielding reduced acceleration values (in all directions) and pitch, roll, and yaw rates. This is anticipated to benefit the future development of personal mobility devices and help realize effective and accessible public transport systems, as well as reduce the number of vehicles in urban areas.

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