<p>Excessive private cars have caused serious problems for the whole society, which seriously damages human well-being and urban sustainable development. This study endeavors to empirically identify the motivational pattern and psychological process involved in individuals’ behavioral intention to use low-carbon transportation modes based on a conceptual framework accommodating two complementary theories, namely the self-determination theory (SDT) and the theory of planned behavior (TPB). Data from a field survey in Zhenjiang, Jiangsu Province, China is utilized to examine a bunch of hypothesized relationships. The results confirm that both SDT extrinsic and intrinsic motivations associated with driving reduction significantly exert positive influences on the proximal antecedents of low-carbon transportation mode-use intention in TPB, justifying the integration of the two differing theories in the transportation background. The direct influence of all three SDT motives on the target low-carbon transportation intention is also significant, and the total effect of extrinsic motivation reveals to be more prominent. From a practical perspective, such findings highlight the importance to enhance people’s feelings about internal dissatisfaction and disappointment, as well as external punishment and regulations on driving in order to effectively trigger their low-carbon transportation intention formation and enactment. Among TPB factors immediately predicting intention for low-carbon transportation modes, perceived behavioral control is confirmed as the most pivotal one. Taken together, the current findings are valuable in providing managerial implications aimed at promoting desirable motivations and travel behavior changes in the pro-environmental direction.</p>