BluFAX Concept

The BluFax Concept

What is Bluetooth?

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 interconnected using short-range wireless communications. Bluetooth uses a low cost transceiver chip to exchange information with other Bluetooth devices within a globally available frequency band of 2.45 GHz.

Bluetooth transceivers that are powered on and are set in the "discover" mode continuously transmit their 48-bit ID (address) for the purpose of identifying a device to communicate with, and to establish a link with the “responding devices”. This process is continuous and will transmit inquiries even if, for example, someone is talking on a mobile phone using a head set.

Every Bluetooth device has a unique 48-bit address that may look like this: OO:18:AF:4B:56:BD. The first half of the number (00:18:AF) is assigned by the manufacturer. The second half of the number (4B:56:BD) is associated with that device. This information is not stored in accessible databases. While device IDs are unique, BluFAX units collect no personal information as part of this process [More information on Privacy Issues].   .

Each BluFAX contains GPS and synchronizes with a common time reference.    


Traveltimes and space mean speed are calculated by BluSTATS software by detecting the signals of common IDs at two locations and subtracting the times of detection.   

 The BluFAX Advantage

Directly measures traveltime and space mean speed. BluFAX provides greater accuracy because traveltime is directly sampled rather than inferred from the point speed detections. This is a leapfrog advance over existing point detection technology, such as inductive loops, radar detectors, and image processors commonly used to infer traveltime. Errors on the magnitude of 30% are possible using conventional detection technology.

Accurate measurement of the origins and destinations (O-Ds) of the overall traffic stream.  Use of BluFAX provides a larger sample size at a cost at a lower cost than is possible with conventional methods. Conventional O-D sampling techniques such as on-road surveys are extremely disruptive to traffic flow. Postcard surveys are invasive to individual privacy. Automatic license plate readers are expensive to install and operate.

Accurate traveltimes on both freeways and arterial streets.  The ability to collect accurate traveltimes on arterials is unprecedented. No general purpose technology currently exists with this capability.

Suitable for use with a variety of modes.   Because Bluetooth devices are generally associated with individuals,  BluFAX can collect data for pedestrians, or for any vehicles occupied by individuals carrying Bluetooth-enabled devices.  

Minimal impact on personal privacy. BluFAX offers greater personal privacy than currently available with automated toll tag tracking, license plate surveys or cellular telephone probes. There is no user account database in existence today that is associated with Bluetooth addresses.  BluFAX sensors can be configured to encrypt Mac IDs before they are stored on-board the device or transmitted to a server for processing.

An open protocol that is applicable globally. Cell phone and automated-toll tag data are only applicable to specific facilities, manufacturers or regions. The Traffax approach can be deployed worldwide, at any scale, on any transportation facility.