Presenter Profile
Alyssa Joachim, MD
Pediatric Surgery Research Fellow
Rady Children's Hospital of Orange County
ajoachim@choc.org
Alyssa Joachim is currently in her 2nd year of research at Rady Children's Hospital in Orange County (formerly CHOC). She completed 3 years of general surgery residency at University of California-San Diego prior to starting her research time. Her research interests related to injury prevention include e-bike research and understanding how the built environment and local policies impact e-bike injuries.
Presentations
Slowing Down Super73 E-Bikes: Did App-Based Speed Restrictions Impact Pediatric Rider Safety?
Alyssa Joachim, MD
John Schomberg, PhD
Romeo Ignacio, MD
Yigit Guner, MD, MS
Amy Lawrence, MD
Laura Goodman, MD, MPH
With growing electric bike (e-bike) ridership, pediatric e-bike crashes are becoming increasingly common and are often more severe than traditional bicycle injuries because of the higher speeds these bikes can achieve. Legislative and manufacturer-based interventions have been implemented to limit e-bikes speeds. One such intervention was Super73’s January 1, 2025, app restriction, which disabled “off-road” mode allowing speeds above 28 mph; without this app, Super73s are a class 2 or 3 e-bike depending on the model, allowing speeds up to 20-28 mph with a throttle, or even higher with pedal assistance or modification. This study assessed whether the change was associated with differences in pediatric crash frequency or characteristics.
We performed a retrospective analysis of police-reported e-bike collisions involving riders ?18 years recorded in the Statewide Integrated Traffic Records System (SWITRS) between 2021-2025. Demographic characteristics, roadway conditions, injury severity, collision factors, and the proportion of crashes involving Super73 e-bikes were compared before and after implementation of the Super73 app restriction.
A total of 115 pediatric crashes involving Super73 e-bikes were identified, 71 (61.7%) of which occurred before the app restrictions and 44 (38.3%) after the app restriction. Median rider age was similar before and after the restriction, at 14 years (interquartile range [IQR] 13-15) prior to the app restriction and 13 years (IQR 12-14) after the app restriction. No significant differences were observed in helmet use, injury severity, roadway conditions, or unsafe riding behaviors before and after the app restriction was implemented. Prior to the app restriction, Super73 e-bikes accounted for as low as 9.0% of e-bike crashes annually in 2022 and up to 17.0% of e-bike crashes in 2024, compared with 12.1% following implementation of the app restriction in 2025.
Super73’s app-based speed restriction limited speeds above 28 mph as of 2025, with pediatric Super73 e-bike crashes showing no significant change in injury severity or crash characteristics following this change. The reduction in proportion of crashes attributable to Super73 e-bikes seen in 2025 requires longer-term study to determine whether it reflects improved safety or reduced ridership.
1. Understand the impact of e-bike app restrictions on Super73 crash characteristics and demographics
2. Understand how implementation of a Super73 speed restriction impacted proportion of crashes that occurred on Super73 e-bikes
3. Understand how e-bike app and/or speed restrictions may be a legislative policy that can help reduce e-bike crashes
When E-Bikes Go Faster: Injury Severity and Crash Patterns in California Pediatric Riders
Alyssa Joachim, MD
John Schomberg, PhD
Marizen Ramirez, MPH, PhD
Nikolas Mendoza
Natalia Solange Ramirez-Mendoza
Bryant Mendoza
Melanie Tacher Otero, MD
April A. Carlson, MD
Spencer Wilhelm, MD
Romeo Ignacio, MD
Amy Lawrence, MD
Yigit Guner, MD, MS
Laura Goodman, MD, MPH
As electric bike (e-bike) popularity continues to rise, the number of injuries resulting from e-bike accidents are also increasing. E-bike crashes can result in a wide spectrum of injuries, and even death, and are often more severe than injuries with traditional bicycles due to the higher associated speeds. E-bikes are generally classified based on speed and throttle presence: class 1 reaches speeds up to 20 miles per hour (mph) with pedal-assist, class 2 includes throttle assistance up to 20 mph, class 3 includes pedal-assist with a top assisted speed of 28 mph, and class 4 exceeds 28 mph using electric assistance. Although many municipalities have introduced legislation restricting pediatric access to higher speed e-bike classes, limited data exists regarding how e-bike class impacts collisions and injuries.
We performed a retrospective analysis of police-reported e-bike collisions involving riders ?18 years recorded in the Statewide Integrated Traffic Records System (SWITRS) between 2021-2025. Demographic characteristics, roadway conditions, injury severity, and collision factors were analyzed and compared by e-bike class.
A total of 384 collisions involving class 1-3 e-bikes and 267 collisions involving class 4 e-bikes were identified. The median rider age was 14 years in both groups; however, class 4 riders were more frequently ages 11-14 (61.7% vs 49.2%) and less likely to be aged 15-18 (35.5% vs 47.9%) compared with riders of class 1-3 e-bikes (p=0.009). Class 4 riders were more frequently male than class 1-3 riders (80.5% vs. 76.3%, p=0.02). Serious injuries occurred more often among class 4 riders compared to class 1-3 e-bike riders (10.8% vs. 5.98%, p=0.05). Riders of class 4 e-bikes were also more likely to be identified as at fault for the collision (65.1% vs 60.9%, p <0.0001), although rates of unsafe riding behaviors did not significantly differ between groups (12.3% vs 10.1%, p=0.37).
Class 4 e-bikes are capable of speeds exceeding 28 mph, often traveling at speeds similar to cars. Despite these risks, a substantial proportion of riders involved in collisions with class 4 e-bikes were children under the age of 15. Pediatric riders of class 4 e-bikes were also more likely to be deemed at fault and to sustain serious injuries following collisions. These findings support ongoing enforcement efforts for age restrictions on high-speed e-bikes and highlight the need for parent and rider education regarding e-bike classification and the associated risks, both physical and legal.
1. Risks associated with higher class (high speed) e-bikes
2. Understanding who is more at risk for e-bike collisions
3. Specific data-driven targets for e-bike education and legislative interventions