ETH Zurich: Scooter-sharing does not help the climate

Better: Own AND use

For the climate, "owning" is better. This is because private e-scooters and e-bikes more frequently replace trips made by car and consequently emit less CO2 than the modes of transport they substitute. Therefore, private micromobility reduces CO2 emissions and benefits the climate overall.

Choice of transportation modes was modeled

To determine the climate effects of shared and private e-micromobility, researchers first needed to understand how users choose between sharing services and established modes of transport. For this purpose, the team collected position data, bookings, and survey data from 540 study participants in the city of Zurich over three months and reconstructed around 65,000 trips using eight different modes of transport, as ETH outlined in a statement. Reck supplemented this with contextual information about the weather and the available mobility options. Using this data, Reck and colleagues developed, for the first time, a model of transportation mode choice that includes shared micromobility, public transport, and common private modes of transportation.

Important basis for transportation planning

Knowledge of transportation mode choice is relevant for planners in both research and practice, according to ETH. Previous studies mostly relied solely on user surveys and sometimes assumed high hypothetical substitution rates for car replacement in their CO2 savings calculations. In contrast, Reck's data-based analysis captures user preferences much more precisely, laying the foundation for realistically modeling micromobility in transportation simulations. This allows for the first time a scientifically grounded prognosis and discussion about the climate impact of new modes of transport, promoting the university’s method.

A climate protection illusion: Sharing is caring

The poorer CO2 balance of shared micromobility thus contradicts the widespread mantra "Sharing is caring," which suggests that sharing (instead of owning) is environmentally friendly, ETH continues.

"This may be true in many areas — I certainly consider the sharing principle to be sensible. However, in terms of micromobility and its climate impacts, the situation seems to be actually reversed," Reck opines.

Zurich is unlikely to be an exception, the authors believe. They expect the results to be transferable to most European cities with good public transportation offerings. The findings should be understood as a call to operators to improve their systems and operations. The study also provides cities with indications on how to effectively integrate and regulate new mobility forms.

"Authorities looking to reduce CO2 in transportation could promote commuting with private micromobility," Reck suggests.

Transportation planners could also work with providers to find ways to better leverage the potential of sharing services for CO2 reduction and car replacement. Ideally, shared e-scooters and e-bikes would expand the catchment area of public transport, facilitate the last mile for commuters in outer districts, and help to smooth peak loads during rush hours, argue the scientists.

"Whether the potential can be realized depends on how we use micromobility in the future," Reck concludes.

For his research, Reck received the "Young Researcher of the Year Award" from the International Transport Forum (ITF) in the summer of 2021. The prestigious think tank awards this prize to young researchers whose work is significant for transportation policy issues. (ETH/Michael Keller/jr)