Pick Your CARbon: User Perceptions of Equivalencies for Carbon Emissions when Selecting Rideshares.

Ridesharing is a popular choice for personal transportation needs. Although more ecologically-friendly than single-occupancy vehicles, there is an opportunity to further reduce CO2 emissions by offering green choices. Here we examine whether providing people with information about CO2 emissions nudges them to make more eco-friendly rideshare decisions. Our study tested what kind of information works best to inform people about carbon emissions, comparing direct CO2 values with more relatable carbon equivalents (e.g., trees). We conducted an online study with 1000 participants who picked between regular and eco-friendly ride options that detailed various carbon-output equivalency interventions (e.g., pounds of coal, number of smartphones charged, etc.). We found that participants are more likely to choose a green ride when presented with information about direct CO2 emissions than when presented with carbon-equivalencies. This study aims to inform future information-based interventions more broadly, beyond the context of ridesharing.