Electric Scooter Injuries and Hospital Admissions in the United States, 2014-2018

Electric scooters (e-scooters) are a novel, rapid, and convenient mode of transportation with increasing accessibility across the United States.¹ E-scooter use may decrease traffic congestion and increase public transit use.² Expansion of e-scooters in dense, high-traffic urban areas will affect rider injury in unknown ways and lead to new policies already implemented by some major cities.³ With the influx of e-scooter availability in urban areas, particularly in the past year,³ we sought to investigate trends of injury and hospital admission.

The National Electronic Injury Surveillance System (NEISS) provides national estimates of injuries that present to emergency departments across the United States (https://www.cpsc.gov/Research--Statistics/NEISS-Injury-Data). We queried NEISS for injuries related to powered scooters (code 5042) from 2014 to 2018, with keyword scooter in the description (n = 1037). We excluded non–e-scooter injuries (n = 49). We used NEISS complex sampling design to obtain US population projections of injuries and hospital admissions. Population estimates from the US Census Bureau (https://www.census.gov/programs-surveys/popest/data/data-sets.html) were used for the direct method of age adjustment. The data source was public, deidentified, and was exempt from the University of California, San Francisco, institutional review board approval. Owing to the use of deidentified data, patient consent was not obtained. We applied linear regression to determine trends of injuries and admissions. We used Stata, version 15 (StataCorp); 2-sided P values less than .05 were considered significant.

There was a dramatic increase in injuries and admissions from 2017 to 2018 associated with e-scooter use. During the study period, a weighted total of 39 113 (95% CI, 28 151-50 074) e-scooter injuries occurred in the United States (988 NEISS cases). Age-adjusted e-scooter injury incidence per 100 000 significantly increased by 222%, from 6 (95% CI, 3-9) to 19 (95% CI, 6-32) (P = .01). There was an increase in age-adjusted hospital admission by 365%, from 0.4 (95% CI, 0-1.0) to 1.8 (95% CI, 0-3.6) (P = .39). Thirty-six percent of those injured across the study period were women. Over the study period, urban hospitals received the highest proportion of patients (78%; 95% CI, 68-85) compared with rural (20%; 95% CI, 13-29) and children’s hospitals (2%; 95% CI, 1-4).

While the incidence of injuries increased over the study period, the body region injured was stable. In 2018, 4707 of 14 651 e-scooter injuries involved the head (32%; 95% CI, 26-38). Upper and lower extremity injuries increased from 1083 (95% CI, 537-1629) to 3747 (95% CI, 1720-5775) (P = .27) and 1721 (95% CI, 1012-2430) to 4707 (95% CI, 2369-7044) (P = .67) (Table 1), respectively. The most common injuries during the study period were fractures (27%; 95% CI, 23-31), contusions and abrasions (23%; 95% CI, 20-28), and lacerations (14%; 95% CI, 12-18).

The proportion of injuries among those aged 18 to 34 years increased by 185%, from 582 of 4582 (13%; 95% CI, 4-31) to 5309 of 14 651 (36%; 95% CI, 25-50) (P < .001) (Table 2). Admissions among those aged 18 to 34 years also increased by 354%, from 30 of 313 (10%; 95% CI, 2-40) to 599 of 1374 (44%; 95% CI, 20-70) (P = .02). There was also a significant increase in injuries among those younger than 18 years, yet the overall proportion compared with other age groups decreased over the study period by 34%.

We report significant increases in e-scooter injuries and admissions between 2014 and 2018, particularly over the last year, with people aged 18 to 34 years becoming the most injured group. The proportion of hospital admissions of people aged 18 to 34 years increased 354%, compared with 2% for people younger than 18 years. Our findings are consistent with a 2019 case series from 2 urban trauma centers.⁴ Despite being unable to account for ridership exposure, the nearly doubling of incident e-scooter trauma calls for improved rider safety measures and regulation.

Study limitations include the lack of detailed clinical reports such as collision scenario, alcohol use, or helmet use. The actual incidence of e-scooter trauma may be underestimated because cases with unclear scooter type were excluded and some riders likely avoided the emergency department despite injury. Future research into pedestrian and cyclist trauma associated with e-scooter use is needed. Creating separate coding for standing and seated scooters may help avoid misclassification of assisted-living scooters with e-scooters.

Nearly one-third of patients had a head injury, more than double the rate of head injuries experienced by bicyclists.⁵ A 2019 study found 4.8% of injured e-scooter riders wore a helmet,⁴ while a multi-institutional case series reported only 2% used helmets.² Previous research has demonstrated helmet use is associated with lower risk of head injury.⁶ E-scooter companies should facilitate and encourage helmet use by increasing helmet access.

Corresponding Author: Benjamin N. Breyer, MD, MAS, San Francisco General Hospital, 1001 Potrero Ave, Ste 3A20, San Francisco, CA 94110 (benjamin.breyer@ucsf.edu).

Accepted for Publication: November 3, 2019.

Published Online: January 8, 2020. doi:10.1001/jamasurg.2019.5423

Author Contributions: Dr Breyer had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Namiri, Cohen, Breyer.

Acquisition, analysis, or interpretation of data: Namiri, Lui, Tangney, Allen, Cohen.

Drafting of the manuscript: Namiri, Lui, Allen, Cohen.

Critical revision of the manuscript for important intellectual content: Namiri, Tangney, Cohen, Breyer.

Statistical analysis: Namiri, Allen.

Administrative, technical, or material support: Namiri, Lui.

Supervision: Namiri, Allen, Cohen, Breyer.

Conflict of Interest Disclosures: None reported.

Funding/Support: The project was supported by an unrestricted gift from Anita and Kevan Del Grande.

Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.