Application of Bluetooth Technology in Traffic Detection, Surveillance, and Traffic Management

In recent years, new technologies for collecting travel time data have emerged that have empowered many applications in transportation systems management. To measure travel time on a roadway, the vehicles have to be either continuously tracked or identified at consecutive points. Identification and re-identification of vehicles is made possible through automatic license plate readers (ALPR) or through electronic toll tag readers where such data are being collected. The latest technology in this category is the Bluetooth traffic detector. Bluetooth is a telecommunications industry specification that defines the manner in which mobile phones, computers, personal digital assistants, car radios, and other digital devices can be easily interconnected using short-range wireless communications. One example of the use of this technology is the interconnection of a mobile phone with a wireless earpiece to permit hands-free operation. Bluetooth-enabled devices can communicate with other Bluetooth enabled devices at a distance from 1 meter to about 100 meters (300 feet). This variability in the communications capability depends on the power rating of the Bluetooth subsystems in the devices. The Bluetooth protocol uses a 48-bit electronic identifier, or tag, in each device called a machine access control address, or MAC address for short. Bluetooth transceivers transmit their MAC ID for the purpose of identifying a device with which to communicate. This “inquiry mode” is used to establish a link with the “responding devices.” Inquiries are made by a Bluetooth transceiver, even while it is already engaged in communication with another device. The continuous nature of this process facilitates the identi-