Beyond private-sphere pro-environmental action: Explaining shared mobility using the Theory of Planned Behavior and solidarity-oriented variables

• Conceptualization of shared mobility as collaborative pro-environmental behavior. • Investigation of solidarity-oriented variables while controlling for constructs of the Theory of Planned Behavior. • Positive connections between universalism and collective response efficacy with shared mobility intention. • Opinion-based social identification was positively related to shared mobility intention. • Solidarity-oriented variables may complement models that aim to explain pro-environmental actions beyond the private-sphere. Shared mobility behaviors can decrease the negative environmental effects of the transport sector, yet they have received limited attention. Models such as the Theory of Planned Behavior (TPB) have been widely used to explain primarily individual private-sphere pro-environmental behaviors (PEB). However, as shared mobility behaviors are not completely limited to the private sphere but require social cooperation, solidarity-focused variables that emphasize social interactions may meaningfully complement the TPB variables. In three university samples (Study 1: N =261, Study 2: N =1411; Study 3: N =544), we tested relationships between the TPB variables and shared mobility, and whether solidarity-oriented variables are relevant predictors of shared mobility beyond the TPB variables. The analyses confirmed attitude ( β = 0.38 − 0.59, p < 0.001) and social norm ( β = 0.17 − 0.43, p < 0.001) as predictors of shared mobility intention. Furthermore, the solidarity-oriented variables universalism ( β = 0.09 − 0.18, p < 0.05) as well as specific collective efficacy ( β = 0.08 − 0.10, p < 0.05) and opinion-based social identification ( β = 0.18, p < 0.001) positively predicted shared mobility intention. Psychological variables showed no consistent connection to self-reported shared mobility behaviors in logistic regressions. We discuss the scope of solidarity-oriented variables that need social cooperation to complementarily explain PEB beyond the private sphere.