This paper concerns the definition and implementation of an add-on interaction system for motorcycles. The system is a vehicle-to-driver communication system and a driver-to-infrastructure communication system, based on a smartphone core and a wireless Bluetooth medium. The system is devoted to increase the safety level of a motorcycle and it is constituted by a vehicle with a CAN bus, a compact embedded electronic implementing a CAN-to-Bluetooth gateway, a smartphone and a Bluetooth helmet. The driver-to-vehicle system is based on an audio interaction located at helmet level. The driver-to-infrastructure is represented by communication via a HTTP protocol. The vocal synthesis, the speech recognition, and the web gateway are resident on the smartphone. This work presents the general hardware and software architecture and some specific web-oriented implementation. An evaluation of the critical aspects of the system is also provided.