BELTON — The large electronic signs stationed on the side of Interstate 35 that report travel times are more than estimates, according to the Texas Department of Transportation, which installed the Bluetooth readers as a means of providing the most accurate real-time data.
About 30 of the so-called “portable changeable message signs” in the Central Texas region are part of TxDOT’s goal of providing useful information to drivers during the multiyear I-35 construction project, TxDOT spokeswoman Jodi Wheatley said.
Contracted by TxDOT, the Texas Transportation Institute at Texas A&M University in College Station in 2011 installed the first of a planned series of signal readers to measure and report actual travel times of points along I-35 from Georgetown to Hillsboro. A year later, TxDOT installed additional signs along a 100-mile stretch of the interstate from Salado to Hillsboro.
The solar-powered readers listen for signals emitted specifically by Bluetooth-enabled devices such as cellphones and GPS units. Monitoring stations along the route then note when the same signal passes separate readers and calculates the travel time for the distance involved.
The monitoring stations do not record license plates or phone calls, and identification numbers emitted by Bluetooth devices are not stored once a vehicle leaves the monitoring zone, Wheatley said.
“Privacy is protected all along the way,” she said.
Once the average travel time between two points is determined, the times are disseminated through a variety of means, including email and Twitter. The overall system will enable TxDOT to provide timely information to travelers to help plan their trips and minimize the impact of construction delays, officials said.
“I-35 is a significant corridor which is vital for both commerce and local traffic, so it’s extremely important that TxDOT and TTI do everything possible to make sure information about lane closures, delays and other construction conditions are relayed to motorists so they can make appropriate travel decisions,” said Bob Brydia, research scientist for the Texas Transportation Institute overseeing the system.
The eight-county Waco district of TxDOT is the only region in Texas currently using the roadside travel signals, but as the widening of I-35 continues, the temporary signals eventually will be replaced with more permanent travel signals installed above I-35 lanes, Wheatley said.