SH-99 Grand Parkway from US-290 to I-45 is now open. No tolls on this segment of SH-99 until February 15.
The Greater Houston Transportation and Emergency Management Center City of Houston Harris County METRO Texas Department of Transportation
Home | Contact Us | About Houston TranStar News Room | Tours

Houston TranStar and Bluetooth™ Traffic Monitoring

Houston TranStar uses various technologies to measure the average speed and travel time of vehicles as they travel along a roadway. Information collected from these technologies is the source for providing travelers with traffic information in various formats including:

In the past, the primary source for measuring speeds and travel times in the Houston region has been from the use of toll tag information. Recently, the Houston TranStar partners have been implementing traffic sensors that make use of Anonymous Wireless Address Matching (AWAM) to measure speeds and travel times along roadways.

Anonymous Wireless Address Matching Using Bluetooth

Houston TranStar's AWAM System detects vehicles equipped with enabled Bluetooth networking devices, including cellular phones, mobile GPS systems, telephone headsets, and in-vehicle navigation and hands-free systems.


Every Bluetooth device has an electronic address, known as a MAC address, used to identify it to other network devices. Each roadside AWAM reader senses these addresses emitted by enabled devices as they pass the reader station.

For real-time applications, the AWAM reader then transmits the time and location of the device to the AWAM host processing system at Houston TranStar. As probes are detected at successive AWAM readers, the host system merges travel time readings to calculate average travel times and speeds for a roadway segment.

A Note About Privacy

The MAC addresses read by AWAM are not directly associated with a specific user and do not contain any personal data or information that could be used to identify or "track" an individual's whereabouts. In addition, all addresses collected by AWAM are anonymized through encryption immediately upon receipt. Users who have privacy concerns are also able to turn off the Bluetooth discovery function of their device which prevents it from being read by AWAM at all.

Unlike the applications on a smart phone that use the GPS functionality, AWAM does not have the ability to "track" vehicles or devices everywhere they go. Also, unlike these applications, AWAM cannot correlate a device address with an individual or vehicle so determining who the device belongs to is virtually impossible. Alternative methods for gathering traffic data, such as those used by GPS (which is utilized by virtually every smart phone) or license plate recognition are more likely to warrant privacy concerns.

An Innovative Practice

Houston TranStar's Bluetooth Traffic Monitoring System has been formally recognized nationally for being a cost-effective innovative practice in traffic monitoring.
ITS America Award Winner 2011 Digital Government Award Winner 2011