It should come as no surprise that when you introduce e-scooters, the impact on a city’s transportation network over time yields less congestion and quicker travel times. But what happens when a city already has scooters and then restricts their use at certain times of day?

Just eight months after the introduction of an e-scooter program, Atlanta implemented a curfew in August 2019 with the stated reason of improving safety. The new rule required vendors to suspend service from 9pm to 4am. This created a natural experiment that would reveal the impacts of curbing micromobility options on a city’s broader transportation system.

A new study from Georgia Tech found the e-scooter curfew led to more car traffic, increased emissions, fewer transportation options in the evening and overnight, and reduced economic activity during these hours.

Congestion effects

The researchers found the e-scooter curfew caused drivers to spend an extra 10-11% more time in traffic than if the scooter ban hadn’t been in place, adding 2 to 5 minutes per trip on average for all impacted drivers. Those minutes add up - the authors estimate that this translates to between 325,000 and 780,000 additional hours of travel for Atlanta drivers per year.

In Lime’s most recent surveys in Atlanta, riders reported using e-scooters to connect to public transit on a quarter of trips. Similarly, 70% stated that one of the primary benefits of Lime was to connect them to other public transit options. By banning scooters, the city removed a valuable first- and last-mile connector to transit, making it more likely travelers would choose cars or ride share instead.

The impacts were even more pronounced on days with major sporting events. When the Atlanta United soccer team played, drivers spent an additional 37% more time in traffic than if the city hadn’t implemented a scooter curfew. Imagine having to spend more time in traffic AND pay $40 for car parking when you could have taken a scooter directly to the stadium at a fraction of the cost!

This is unsurprising, as we see 9% more Lime e-scooter trips on average in Downtown Atlanta, where Mercedes Benz stadium is located, on days when Atlanta United plays compared to the rest of the city.

Mode shift from scooters to cars

The Georgia Tech researchers argue that the increased travel time for drivers is a result of travelers switching from shared micromobility to cars, taxis, and ride share in reaction to the scooter curfew. This is an additional, high-quality piece of evidence showing how micromobility leads to mode shift from higher-polluting modes like motorized vehicles.

The results of the study are consistent with the City of Atlanta’s survey results that showed 42% of shared scooter trips replaced a motor vehicle trip and 52% of riders used scooters at least a few times per month. A literature review by UC Davis researchers suggests that this mode shift pattern is consistent with other US cities.

Perhaps even more concerning than the increased congestion is the increased air pollution and carbon emissions that come from people switching from shared scooters to motor vehicles. A recent Fraunhofer ISI study found that our Gen4 e-scooters and e-bikes have carbon footprints on par or below public transit and electric cars, and as such, reduce cities’ transportation sector carbon emissions. The study found that in Seattle, an average shared scooter trip reduced carbon emissions by 38 grams per passenger kilometer, and when considering shared scooter trips replacing a taxi or ride share, the carbon savings grow even larger: on average 541 grams CO2 per trip.

Who was most impacted by the scooter curfews?

Nighttime curfews prevent a large number of travelers from using shared scooters and bikes, even though there are no similar bans in place for other modes of travel. In Oklahoma City, 35% of Lime e-scooter trips are taken during Atlanta’s curfew hours (9 pm to 4 am) and in Tampa 32% of trips are taken during these hours. This amounts to about a third of total trips in these cities, underscoring the strong demand for mobility options during these hours.

While the curfew in Atlanta was implemented in the name of safety, one area of public safety was overlooked according to Atlanta writer Maya Kroth. When the curfew went into effect, Ms. Kroth wrote in Atlanta Magazine:

“Banning scooters at night does little to improve public safety; in fact, for women like me who relied on them to help make the last mile of our journey a little safer, it only makes things worse.”

When people feel unsafe walking at night, e-scooters provide an option that can help them move quickly to their destination. Limiting access to this option removes the sense of security it offers, leaving people to choose between an uncomfortable walk, or a more expensive and polluting car trip.

What’s next

Beyond Atlanta, other cities in the United States (Cincinnati, Cleveland, St Louis, and Detroit) and around the world (Auckland) also impose curfews on their shared micromobility programs. This new research, and our internal data, show that these bans end up backfiring, leading to increased car traffic, more pollution, and fewer transportation options for people looking to get around cities at night.

We hope this research will lead policymakers to reconsider their bans and work with the micromobility industry to identify alternative solutions.