Monday, October 27, 2025

Study: Electric scooters boost rideshare trips but reduce bikeshare demand, raise new safety concerns

University of Illinois at Urbana-Champaign, News Bureau

image:
The introduction of shared e-scooters boosted demand for ridesharing services but reduced bikeshare usage — and was also linked with higher rates of street and vehicle-related crime, says new research co-authored by Unnati Narang, a professor of business administration at Illinois.
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Credit: Photo by Gies College of Business

CHAMPAIGN, Ill. — A new study from a University of Illinois Urbana-Champaign marketing expert finds that electric scooters, one of the fastest-growing forms of urban transportation, reshape city mobility in unexpected ways.

The introduction of shared e-scooters in Chicago boosted demand for ridesharing services but reduced bikeshare usage — and was also linked with higher rates of street and vehicle-related crime in neighborhoods, says new research co-authored by Unnati Narang, a professor of business administration at the Gies College of Business.

The results of the study, which is a joint project with Ruichun Liu of San José State University and a former Illinois graduate student, challenge common assumptions about the benefits of e-scooters, Narang said.

“E-scooters are hailed as an environment-friendly innovation that is spurring retail activity, but their impact goes beyond what we know in the marketing literature,” she said. “Our study is the first to document the effects of e-scooters beyond retail and restaurants and show how they are reshaping shared mobility systems and even public safety in ways that policymakers need to take seriously, because they accrue economic and environmental costs.”

The researchers analyzed the introduction of e-scooters in Chicago during the summer of 2019, when the city allowed 10 companies to deploy e-scooter rentals across a 50-square-mile area on the west and northwest sides of the city.

Using data from more than eight million rideshare trips, 750,000 bikeshare rides and detailed crime reports across 866 census tracts, they applied a statistical method known as “generalized synthetic control” to measure how e-scooter access changed travel and crime patterns compared to similar neighborhoods without them.

Their analysis covered 41 weeks of data, capturing both pre- and post-rollout trends in mobility and safety.

E-scooter availability led to a 15.7% increase in short rideshare trips, but bikeshare programs saw a 7.6% decline in trips in areas with scooter access, suggesting that riders often substituted e-scooters for rental bikes.

“The increased rideshare trips from e-scooters reflects what we call a category expansion effect,” said Narang, the John M. Jones Fellow of Marketing and Deloitte Scholar. “E-scooters encourage people to take trips they might not have otherwise made, often combining trips with ridesharing. For example, riding an e-scooter to dinner, then calling a rideshare vehicle to get home. Or going to the grocery store but needing a ride back with grocery bags. But we also found that e-scooters don’t add to bikeshare demand. They directly compete with it, which is a classic case of category cannibalization despite greater need for new trips overall.”

While e-scooters expanded mobility and generated new economic activity, they also coincided with a 17.9% rise in reported crimes, concentrated in street and vehicle-related offenses such as car break-ins and thefts.

The researchers emphasized that this rise in crime represents a hidden social cost that cities should consider when evaluating urban transportation policies.

“E-scooters are portable and fast, which makes them attractive tools for crimes of opportunity,” Narang said.

The impacts of e-scooters also weren’t evenly distributed across neighborhoods, the researchers noted.

In areas with higher proportions of minority residents, ridesharing increased compared to low-minority areas, but those same communities also saw an uptick in crime. Bikeshare substitution, by contrast, was strongest in lower-minority neighborhoods.

Age patterns also showed similar disparities. In younger neighborhoods, scooters were associated with a 20.6% increase in crime, much higher than in older areas.

“These patterns suggest that the benefits and costs of e-scooters aren’t evenly distributed, and e-scooters may inadvertently worsen inequities,” Narang said. “Communities of color and younger neighborhoods bear a disproportionate share of the crime increases.”

Despite their eco-friendly image, e-scooters also may not yield environmental gains because they spur an increase in short rideshare trips instead of replacing them.

“Policymakers often see e-scooters as a green alternative, but because they increase short rideshare trips rather than substituting for them, their net environmental effect is negative,” Narang said. “In fact, we found that although rented e-scooters contributed about $8.1 million in ridesharing revenues, they also had an unintended negative environmental effect amounting to over 800 metric tons of carbon emissions per year.”

To offset that volume of annual emission, “you’d need around 36,000 trees growing for one full year,” Narang said. “You can explain the trade-off with other similar environment initiatives and some quick back-of-the-envelope calculations.”

The findings highlight the need for more nuanced e-scooter regulation, the researchers said. Cities may need to invest in protected lanes, adopt safety campaigns, rollout strategies that limit crime opportunities and engage with communities to ensure equitable benefits, according to the paper.

“Cities should not assume that e-scooters automatically promote sustainability or level the playing field in terms of mobility,” Narang said. “They create a lot of externalities, and regulation and planning must address safety and fairness head-on.”

To make their findings accessible, the researchers developed a companion research app that allows policymakers and citizens to explore e-scooter data interactively. The tool can model how future e-scooter rollouts might affect different communities across the U.S.

“We want our work to be actionable,” Narang said. “The app gives stakeholders the ability to anticipate how e-scooters might affect their own cities and make more informed policy decisions. The app allows users to input a ZIP code and makes predictions based on our underlying effects as well as chat with an AI agent.”

The research will be published by the Journal of Marketing.

Journal

Journal of Marketing

DOI

10.1177/00222429251393987

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

“How E-Scooters Impact Shared Mobility and Consumer Safety”

Article Publication Date

23-Oct-2025

How animals get their spots, and why they are beautifully imperfect

University of Colorado at Boulder

Simulated hexagon pattern formation — video:
A mixture of two types of pigment-producing cells undergoes diffusiophoretic transport to self-assemble into a hexagonal pattern.
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Credit: Siamak Mirfendereski and Ankur Gupta/CU Boulder

From tiger stripes to leopard spots, the animal world is full of distinctive and intricate patterns.

In a new study, CU Boulder scientists refined their previous theory of how animal patterns form and successfully recreated imperfections in natural designs, like irregular spots on a leopard. The new mechanism, described October 27 in Matter, could lead to materials that can respond to their environment, such as fabrics that change color on demand for camouflage.

“Imperfections are everywhere in nature,” said Ankur Gupta, the study’s lead researcher in the Department of Chemical and Biological Engineering. “We proposed a simple idea that can explain how cells assemble to create these variations.”

For decades, scientists have been trying to crack the code of how different animal patterns emerge from a mass of developing cells. In 1952, mathematician Alan Turing hypothesized that as tissue develops, it produces chemical agents that diffuse in the system in a process similar to pouring milk into coffee. Some of these chemicals activate pigment-producing cells, forming spots. Other chemicals inhibit these cells, creating the blank spaces in between.

But just as milk clouds the coffee, computer simulations based on Turing’s theory produced spots that were blurrier than those found in nature.

In 2023, Gupta and his collaborators improved upon Turing’s theory by adding another mechanism called diffusiopherosis, a process where diffusing particles pull other particles along with them. It’s the same principle that helps laundry get clean: As soap diffuses out of the laundry into water, it drags dirt out from the fabric.

When Gupta simulated the purple-and-black hexagon pattern seen on ornate boxfish, a flashy species found in the seas off Australia, he found that diffusiopherosis could generate patterns with sharper outlines than Turing’s original model.

But the team’s results were a little too perfect. All the hexagons were the same size and shape, and the spaces between them were identical.

In nature, no animal has flawless patterns. A zebra’s black stripes vary in thickness, and the hexagons on the boxfish are never perfectly uniform.

So Gupta and his team set off to improve the diffusiopherosis model.
They found that by giving individual cells defined sizes and modeling how each one moved through tissue, their simulations began producing imperfect patterns and textures.

Imagine ping-pong balls of different sizes traveling through a tube. Larger balls would create thicker outlines than smaller ones. When bigger cells cluster, they form patterns that are broader. Sometimes the balls bump into one another and jam the tube, breaking up a continuous line. When cells experience that, they create breaks in the stripes.

“We are able to capture these imperfections and textures simply by giving these cells a size,” Gupta said. Their simulations showed breaks and grainy textures that look far more like what’s found in nature.

In the future, Gupta plans to incorporate more complex interactions among cells and with the background chemical agents to improve their simulations.

Humans have always drawn inspiration from nature. Bats’ ability to navigate using echoes led to sonar technology, which locates objects through sound. Gupta said understanding how pattern-making cells assemble could help engineers design synthetic materials that can change colors based on the environment, much like a chameleon’s skin. It could also help design effective approaches to deliver medicine to a specific part of the body.

“We are drawing inspiration from the imperfect beauty of natural system and hope to harness these imperfections for new kinds of functionality in the future,” Gupta said.

Top: A male ornate boxfish. Bottom: Simulated hexagon and stripe patterns obtained by diffusiophoretic assembly of two types of cells on top of the chemical patterns.
Credit
The Birch Aquarium/Scripps Institution of Oceanography; Siamak Mirfendereski and Ankur Gupta/CU Boulder