E-Bikes Cause Explosion in Brain Injuries
In 2018, only 8% of bicycle and scooter traumas recorded at New York's Bellevue Hospital involved electric versions. By 2023, that number exploded to over 50%. One-third of patients suffered traumatic brain injury. Half required surgery. And the most disturbing finding of all: pedestrians struck by e-bikes and electric scooters suffer brain injuries at nearly double the rate of the vehicle operators themselves. These are the numbers from a five-year study conducted by NYU Langone Health and published in the journal Neurosurgery in April 2026 — and they reveal a public health crisis that has been silently building on the streets of the world's major cities.
While governments and companies celebrate the electric micromobility revolution as a solution for traffic and pollution, emergency rooms tell a different story. A story of fractured skulls, emergency surgeries, and permanently altered lives. And the biggest victims are not who you might expect.
What Happened
The NYU Langone Health study is the most comprehensive ever conducted on the impact of e-bikes and electric scooters on the hospital trauma system. Led by researchers from NYU Langone's Department of Neurosurgery and based on data from Bellevue Hospital — the largest public trauma center in the United States — the research analyzed all patients admitted for bicycle and scooter accidents between 2018 and 2023.
The results, published in the journal Neurosurgery, are alarming across virtually every metric analyzed.
The most striking finding is the speed at which electric vehicle accidents came to dominate trauma statistics. In 2018, when the study began, e-bikes and electric scooters represented just 8% of bicycle and scooter-related trauma cases at Bellevue. By 2023, the final year of the study period, that number had jumped to over 50% — a more than sixfold increase in five years.
Currently, e-bike and electric scooter accidents account for nearly 7% of all trauma patients admitted to Bellevue Hospital, regardless of cause. To put this in perspective, we are talking about a single type of accident that now rivals traditional trauma categories such as falls from height and physical assaults.
The severity of injuries is equally concerning. Among patients admitted for e-bike and electric scooter accidents, one-third suffered traumatic brain injury — ranging from mild concussions to potentially fatal intracranial hemorrhages. More than two-thirds of patients (66%+) required hospital admission, indicating that the majority of cases are not superficial injuries that can be treated and discharged the same day.
The numbers become even more severe when we examine the need for intensive care and surgical interventions. Approximately 30% of patients required admission to the intensive care unit (ICU), and 50% underwent some type of surgery. Additionally, 26% of patients presented injuries to the skull or face — facial fractures, skull base fractures, and other injuries that frequently leave permanent sequelae.
The most common mechanism of injury was collision with motor vehicles — cars, buses, and trucks — followed by falls. This pattern suggests that current road infrastructure, designed to separate pedestrians from cars but not necessarily from high-speed electric bicycles, is inadequate to handle the new reality of micromobility.
But the study's most disturbing finding concerns pedestrians. People who were simply walking and were struck by e-bikes or electric scooters suffered brain injuries at nearly double the rate of the vehicle operators themselves. This finding inverts the predominant narrative about micromobility safety, which has traditionally focused on risks to cyclists and scooter riders while ignoring the growing danger to those on foot.
Context and Background
To understand the magnitude of the problem revealed by the NYU Langone study, it is necessary to understand the context of the global explosion in electric micromobility in recent years.
The global e-bike market has grown exponentially over the past decade. Industry estimates indicate that more than 40 million e-bikes were sold worldwide in 2023, with projections for continued growth. In the United States, e-bike sales have surpassed electric car sales for several consecutive years. In Europe, countries like the Netherlands, Germany, and France have seen e-bikes become the fastest-growing mode of transportation.
In New York City, the epicenter of the study, the transformation was particularly dramatic. The city saw an explosion in e-bike use driven by three converging factors: the COVID-19 pandemic (which led many people to avoid public transportation), the exponential growth of app-based delivery services (which rely heavily on e-bikes), and municipal policies that incentivized micromobility as an alternative to cars.
Delivery workers for apps like DoorDash, Uber Eats, and Grubhub became ubiquitous on New York streets, most using e-bikes that can reach speeds of 15 to 28 mph — significantly faster than conventional bicycles, which rarely exceed 12 mph in urban environments. This speed difference is crucial: the kinetic energy of an impact increases with the square of velocity, meaning an e-bike at 25 mph carries four times more impact energy than a conventional bicycle at 12 mph.
The regulatory problem compounds the situation. In the United States, the legal classification of e-bikes varies enormously between states and municipalities. Some jurisdictions treat them as ordinary bicycles, with no license, registration, or helmet requirements. Others have attempted to impose stricter regulations but face enforcement difficulties. In New York, e-bike legislation has changed multiple times in recent years, creating confusion for both riders and pedestrians about where and how these vehicles can operate.
Shared electric scooters, introduced by companies like Lime, Bird, and Spin, added another layer of complexity. These vehicles are frequently used by people with no prior experience, on crowded sidewalks and bike lanes, often without helmets. The combination of inexperience, speed, and inadequate infrastructure creates a scenario ripe for serious accidents.
The lack of dedicated infrastructure is a critical factor. Most cities, including New York, do not have enough protected bike lanes to accommodate the growing volume of e-bikes and electric scooters. This forces these vehicles to share space with cars on busy traffic lanes or with pedestrians on sidewalks and walking areas — both situations significantly increasing the risk of accidents.
Another frequently overlooked aspect is the lithium battery issue. E-bikes and electric scooters use lithium-ion batteries that, when damaged in accidents, can cause fires and explosions. In New York, fires caused by e-bike batteries have become a growing concern, with the Fire Department recording hundreds of incidents in recent years. While this risk is not directly related to the brain injuries documented in the NYU Langone study, it illustrates the breadth of safety challenges associated with electric micromobility.
If you are interested in how technology impacts health and safety, also check out our article on how artificial intelligence is transforming medical diagnostics and the most surprising scientific discoveries of 2026.
Impact on the Population
The data from the NYU Langone study reveals an impact that extends far beyond hospital statistics. The consequences spread across multiple dimensions of urban life — from the healthcare system to city planning, from family economics to pedestrian psychology.
Healthcare System Burden
The fact that e-bike and electric scooter accidents now represent nearly 7% of all trauma patients at Bellevue Hospital is an indicator of significant pressure on the healthcare system. Each patient with traumatic brain injury requiring ICU care and surgery represents costs that can easily exceed hundreds of thousands of dollars. When 50% of patients need surgery and 30% require intensive care, the financial impact on the hospital system is substantial.
In the United States, where healthcare costs are already the highest in the world, this new trauma category represents an additional burden on both public hospitals and insurers. For patients without health insurance — a reality for many app-based delivery workers who use e-bikes — a traumatic brain injury can mean devastating medical debt compounding the physical aftermath.
Comparative Table: Evolution of the Problem
| Aspect | 2018 | 2023 | Change |
|---|---|---|---|
| % traumas from e-bikes | 8% | 50%+ | +525% |
| Brain injuries | Rare | 1 in 3 patients | Explosion |
| Hospitalizations | Low | 66%+ of cases | Critical |
| Surgeries required | Low | 50% of cases | Alarming |
| Skull/face injuries | Low | 26% of cases | Severe |
| Pedestrians with brain injury | Rare | 2x rider rate | Emergency |
| % of total Bellevue traumas | Negligible | ~7% | Emerging category |
Pedestrians: The Invisible Victims
The finding about pedestrians is particularly concerning because it challenges the predominant narrative about micromobility safety. Safety campaigns, regulations, and public debates have focused almost exclusively on protecting e-bike and scooter operators — encouraging helmet use, respecting speed limits, using bike lanes.
But the NYU Langone study shows that pedestrians are, proportionally, the greatest victims. Suffering brain injuries at nearly double the rate of operators means that walking on the streets of a major city has become significantly more dangerous with the proliferation of electric micromobility vehicles.
There are clear biomechanical reasons for this disparity. Pedestrians struck by e-bikes or electric scooters are completely unprotected — no helmet, no vehicle structure to absorb part of the impact, and frequently no advance warning that would allow a defensive reaction. The impact is sudden and direct, often striking the head when the pedestrian is thrown to the ground.
E-bike operators, on the other hand, while also vulnerable, have at least some awareness of risk and, in some cases, wear helmets. Additionally, in collisions with motor vehicles, the e-bike operator frequently has a fraction of a second to react — braking, swerving, or bracing for impact — an advantage that a pedestrian struck by surprise does not have.
Psychological and Behavioral Impact
Beyond the documented physical injuries, there is a growing psychological impact on the urban population. Pedestrians in cities with high concentrations of e-bikes report anxiety when walking on sidewalks and crossing streets, especially in areas where e-bikes travel at high speeds and frequently disregard traffic signals.
Elderly people and those with reduced mobility are particularly affected. The silent speed of e-bikes — which, unlike motorcycles, produce no significant noise — makes it difficult for pedestrians with reduced hearing to perceive an approaching vehicle. This "sonic invisibility" is a risk factor that does not exist with conventional bicycles (slower) or motor vehicles (louder).
Implications for Urban Planning
The NYU Langone study has direct implications for urban planning. Cities that invested heavily in micromobility infrastructure — bike lanes, sharing stations, favorable regulations — now need to reconsider whether this infrastructure is adequate for vehicles that are fundamentally different from conventional bicycles in terms of speed and mass.
The central question is: should we treat e-bikes as bicycles or as a separate vehicle category? The study strongly suggests the latter. E-bikes reaching 25+ mph have more in common with mopeds than with pedal bicycles, and infrastructure and regulation should reflect this reality.
What Stakeholders Are Saying
The researchers at NYU Langone Health were emphatic in presenting the study's results. The neurosurgery team that conducted the research emphasized that the numbers represent a trend showing no signs of slowing and requiring immediate action from legislators and urban planners.
The study authors stressed that the growth from 8% to over 50% in just five years is not a statistical fluctuation — it is a structural change in the epidemiology of urban trauma. They warned that without significant interventions, the numbers will continue to grow as e-bike and electric scooter adoption expands.
Road safety experts who analyzed the study noted that the data confirms what emergency professionals had been observing anecdotally for years: that e-bikes and electric scooters are creating a new trauma category that the healthcare system was not prepared to absorb.
Micromobility advocates acknowledged the severity of the data but argued that the solution is not to restrict e-bikes and electric scooters, but rather to invest in adequate infrastructure and smart regulation. They pointed out that in cities with extensive protected bike lanes and clear regulations, rates of serious accidents are significantly lower.
Pedestrian organizations, on the other hand, expressed concern that the micromobility industry's interests are being prioritized over pedestrian safety. They emphasized that the finding about pedestrians suffering brain injuries at double the rate of operators should be the center of public debate, not a footnote.
Urban planners consulted about the study acknowledged that current infrastructure is inadequate. Many bike lanes were designed for conventional bicycles moving at 10-12 mph, not for e-bikes that can reach double that speed. The mixing of speeds in shared bike lanes creates risks for both conventional cyclists and pedestrians crossing these lanes.
Public health professionals warned that the problem is global, not just a New York issue. Cities in Europe, Asia, and Latin America experiencing similar electric micromobility booms will likely face — or already face — similar injury patterns. The Bellevue study, they argued, is an early warning for the world.
Next Steps
The NYU Langone Health study is already generating concrete discussions about regulatory and infrastructure changes at multiple levels of government.
Regulation and Legislation
In the United States, several states and municipalities are reviewing their e-bike legislation in light of the new data. The most discussed proposals include:
Mandatory helmets: Currently, most American jurisdictions do not require helmets for adult e-bike operators. The NYU Langone study, by demonstrating that one-third of patients suffer traumatic brain injury, significantly strengthens the argument for mandatory helmet use. Previous studies have shown that helmet use reduces the risk of traumatic brain injury by 48-85%, depending on helmet type and impact severity.
Speed limits: Proposals to electronically limit the maximum speed of e-bikes in urban areas are gaining traction. Some European cities have already implemented reduced speed zones for e-bikes, using geofencing technology that automatically limits vehicle speed in certain areas.
Licensing and registration: The idea of requiring licenses and registration for e-bikes above a certain power threshold is being debated in several states. Proponents argue this would allow better enforcement and accountability in case of accidents. Critics warn that bureaucracy could discourage e-bike use, negating their environmental and mobility benefits.
Mandatory insurance: Some proposals include requiring liability insurance for e-bike operators, similar to what is required for motor vehicles. This would ensure that accident victims — especially pedestrians — have access to financial compensation for injuries suffered.
Infrastructure
The study reinforces the urgent need for dedicated infrastructure that physically separates e-bikes from pedestrians and motor vehicles. The most promising proposals include:
Protected high-speed bike lanes: Dedicated lanes for e-bikes, separated from both sidewalks and motor vehicle lanes by physical barriers. These lanes would be designed to accommodate speeds up to 25 mph, with their own signage and traffic signals.
Speed separation in bike lanes: In existing bike lanes, creating separate lanes for conventional bicycles (slower) and e-bikes (faster), similar to lane separation on highways.
Intersection redesign: Intersections are the highest-risk points for collisions between e-bikes and pedestrians. Redesigning these areas with better visibility, specific signage, and dedicated signal phases can significantly reduce accident risk.
Technology and Innovation
E-bike manufacturers are being pressured to incorporate more advanced safety technologies, including:
- Automatic emergency braking systems (AEB) adapted for e-bikes
- Audio alerts that warn pedestrians of an approaching vehicle
- GPS-based speed limiters that automatically reduce speed in high-risk zones
- High-visibility lights and enhanced reflectors to improve detection by pedestrians and drivers
Future Research
The NYU Langone study authors indicated that additional research is needed on several fronts: multicenter studies including hospitals from different cities and countries to determine whether the patterns observed at Bellevue are universal; cost-effectiveness analyses of different regulatory and infrastructure interventions; longitudinal studies on the long-term consequences of traumatic brain injuries caused by e-bike accidents; and investigations into the effectiveness of different helmet types in preventing brain injuries at typical e-bike speeds.
Closing
The five-year study from NYU Langone Health, published in the journal Neurosurgery, leaves no room for ambiguity: e-bikes and electric scooters are causing a brain injury crisis in cities. The jump from 8% to over 50% of bicycle and scooter traumas in just five years, combined with alarming rates of traumatic brain injury, hospitalizations, surgeries, and intensive care, constitutes a public health emergency that can no longer be ignored.
The finding about pedestrians — suffering brain injuries at nearly double the rate of operators — is particularly urgent because it affects people who did not choose to participate in the micromobility revolution. Walking down the street should not be a risky activity, but the data shows that in cities with high concentrations of e-bikes and electric scooters, it is becoming exactly that.
Electric micromobility has real and important benefits — reduced emissions, traffic relief, transportation accessibility. But these benefits cannot be achieved at the expense of the safety of the most vulnerable citizens. The path forward requires smart regulation, adequate infrastructure, and a fundamental shift in how we think about the coexistence of electric vehicles and pedestrians in urban spaces.
The numbers from Bellevue Hospital are a warning. The question now is whether cities around the world will heed that warning before their own emergency rooms tell the same story.
