In this paper, we propose a Vehicular Surveillance and Sensing System (VS3), which targets at car security and tracking applications. VS3 can be triggered by events detected inside or outside a car, such as abnormal air quality, potential burglary, and identification of some target vehicles (such as stolen cars). Via a 3G module, a user can interact with VS3 via multimedia communications. For security applications, we show how VS3 detects an abnormal CO2 level or potential car burglary, notifies the vehicle owner, and then interacts with the owner. For tracking applications, we show how VS3 identifies potential stolen vehicles, transmits reports to the police department, and get neighboring cars involved to cooperatively track suspicious vehicles. This paper demonstrates our current prototype.