San Diego County counted 865 emergency department visits and 186 hospitalizations tied to electric bicycles in a single year, and its health department has now told clinicians to start treating e-bike use as something to ask about during ordinary checkups.
The county's health advisory, issued through the California Health Alert Network, uses 2024 data and states plainly that "youth are disproportionately affected." Children under 12 accounted for 56 of the emergency visits and seven of the hospitalizations.
For parents, the useful part of the advisory is not the injury count. It is the section explaining which e-bikes a child is legally allowed to ride, because the answer depends on a class system most families have never been told about.
What the County Data Shows
The injuries were not concentrated in one part of the county. North Coastal recorded the most emergency visits at 246, followed by North Inland at 194 and North Central at 157. South recorded 97, East 90, and Central 81.
Hospitalizations followed a different pattern. North Coastal again led with 48, but Central recorded 29 hospitalizations from only 81 emergency visits, and South recorded 29 from 97 visits. A higher ratio of admissions to visits suggests more severe injuries, though the advisory does not analyze why.
The county attributes the rising burden to increasing e-bike availability and use, and to the basic physics involved. E-bikes reach higher speeds than standard bicycles, and speed drives both the likelihood and the severity of injury, particularly for younger riders with less developed judgment and reaction time.
The Class System Parents Should Know
California law defines three classes of e-bikes, and the rules differ meaningfully.
Class 1 is pedal-assist only, meaning the motor engages when the rider pedals, with a maximum assisted speed of 20 mph. Class 2 adds a throttle, so it can move without pedaling, also capped at 20 mph. Class 3 is speed pedal-assist with an assisted speed up to 28 mph, and the advisory notes it is not suitable for trails and bike paths.
The age and helmet rules follow from that. Class 1 and Class 2 have no minimum age, and riders under 18 must wear a helmet. Class 3 riders must be at least 16 years old and wear a helmet. Helmets are required for all riders and passengers under 18 regardless of class. Passengers are permitted only if the bike is designed to carry them.
Two details in the advisory are easy to miss and worth checking at home. In California, anything over 750 motor watts is legally a moped or motorcycle rather than an e-bike, which carries entirely different licensing requirements. And some e-bikes are modified after purchase to exceed the limits set for their class, which can move a bike out of the category the family believes it is in.
The advisory also cites a Consumer Product Safety Commission recommendation that children aged 9 through 12 should not operate any product that travels faster than 10 mph. Every class of e-bike exceeds that.
What the Advisory Asks Clinicians to Do
The county is asking pediatricians and family physicians to fold e-bike questions into visits they are already conducting.
At well-child visits and injury visits, that means asking whether the child rides, what type of bike, how much training and experience they have, and whether they ride on roads. It also means counseling on helmet use, double-riding risk, and the state laws above.
The advisory points families toward the California Highway Patrol's electric bicycle safety and training course and to Ride Ready San Diego, a program run jointly by Rady Children's Hospital, Safe Kids San Diego, Scripps, UC San Diego and the San Diego Bicycle Coalition.
There is a surveillance ask as well. Specific ICD-10 codes for e-bike injuries have existed since 2023: V28.01XA for nontraffic incidents and V28.41XA for traffic-related ones, and the county wants clinicians using them consistently.
MedicalDaily Evidence Check
These are county surveillance counts, not a study, and the advisory is transparent about the main limitation: underreporting is likely because e-motorcycles are sometimes misclassified as e-bikes and because coding practices vary.
That cuts in a specific direction. The 865 figure is more likely an undercount than an overcount, but it also means the split between true e-bikes and higher-powered vehicles inside that number is uncertain.
The data also cannot show what caused the injuries. Emergency visit counts do not distinguish between a rider struck by a car, a solo fall, a passenger injury, or a crash on a modified bike. Prevention advice that follows from the numbers is reasonable, but the numbers do not by themselves establish which intervention would help most.
Finally, this is one county's 2024 data. It reflects a coastal Southern California county with year-round riding weather and high e-bike adoption, and it should not be read as a national injury rate.
What Parents Can Do Before the Rest of Summer
Find out which class the bike in your garage is. It is usually printed on a sticker on the frame near the bottom bracket or on the down tube, along with the motor wattage and top assisted speed.
Match that to the rider. A 14-year-old on a Class 3 bike is riding illegally in California, and a bike modified past its class limits may not be an e-bike at all in legal terms.
Make the helmet non-negotiable and fit it properly. Helmets are legally required for every rider and passenger under 18 in California regardless of class, and a loose helmet does substantially less.
Address double-riding directly. Carrying a friend on a bike not designed for a passenger is both illegal and a recurring injury pattern, and it is one of the easier rules for a family to enforce.
Sign the rider up for a training course before adding road riding, rather than after a near miss.
What Happens Next
The county has not announced a follow-up data release, and 2025 injury figures have not been published. Because the advisory asks clinicians to improve ICD-10 coding, future counts may rise partly for surveillance reasons rather than because injuries increased, and that distinction will matter when the next numbers appear.
Parents in other metro areas can ask their own county health department whether it tracks e-bike injuries, since several jurisdictions have begun to. MedicalDaily will follow the county's next surveillance update and any state legislative action on e-bike classes.
Frequently Asked Questions
How many e-bike injuries did San Diego County record? 865 emergency department visits and 186 hospitalizations in 2024, including 56 visits and seven hospitalizations among children under 12.
What are the three e-bike classes? Class 1 is pedal-assist only up to 20 mph. Class 2 adds a throttle, also up to 20 mph. Class 3 is speed pedal-assist up to 28 mph.
How old must a child be to ride? Class 1 and Class 2 have no minimum age in California. Class 3 riders must be at least 16.
Are helmets required? Yes. All riders and passengers under 18 must wear helmets on any class of e-bike in California.
Is a high-powered e-bike still an e-bike? Not in California. Anything over 750 motor watts is legally a moped or motorcycle with different requirements.
Why does the county say the data may be incomplete? Because e-motorcycles are sometimes misclassified as e-bikes and coding practices vary, which likely leads to undercounting.
Where can my child get e-bike safety training? The California Highway Patrol offers an electric bicycle safety course, and Ride Ready San Diego provides local training through Rady Children's Hospital and partner organizations.
