The automotive Internet of Things (IoT) is an emerging research field by applying the IoT into the intelligent transportation system. Information sharing among objects such as smart mobile devices and vehicles' sensors plays an important role in strengthening their partnership in the vehicular environment. In this paper, we first consider message trading and propose a community-based information sharing (CIS) mechanism to motivate all objects to engage in sharing traffic events with each other. Specifically, a message processing algorithm and a message generating algorithm are proposed to handle incoming messages originated from other objects and to share new traffic events with others, respectively. Since CIS only uses private information, e.g., location data, locally, the proposed mechanism also ensures the privacy of all objects during information sharing. Simulation results demonstrate that the proposed mechanism can effectively improve the quality of experience of human-beings in terms of the average arriving delay.