Over the past 60 years, drivers have seen countless changes on Texas roadways — not only in how they’re used by drivers but in how they’re built and maintained. Yet one thing remains constant: the partnership between the Texas Department of Transportation (TxDOT) and the Texas A&M Transportation Institute (TTI).
These two agencies work together to create a state transportation network that sets the standard for the nation. TTI research expertise helps advance TxDOT’s state of the practice, most notably in the areas of traffic operations and roadway maintenance.
Managing Our Lanes More Efficiently
In 1979, Houston, Texas — recovering from a 30-year population boom — was running out of highway capacity. The result? Increasing traffic congestion. TTI researchers worked with the Texas State Department of Highways and Public Transportation (now TxDOT) and the agency that became the Metropolitan Transit Authority of Harris County (Houston METRO) to try something different.
“One of the approaches developed was to take a lane of off-peak traffic and assign it for bus-only use in the peak direction of travel on I-45 North,” says TTI Executive Associate Director Katie Turnbull. “A lot of people thought ‘this is interesting, but it isn’t going to work.’ But it did.”
The project was unique because it created the longest freeway contraflow lane at the time and operated during both peak times.
“This was a really innovative idea that spurred the high-occupancy vehicle [HOV] network you have today throughout the state as well as nationally. TTI was responsible for the technical work and helped maintain continuity across changes in both the Highway Department and Houston METRO,” says Turnbull.
In 2005, Beverly Kuhn, head of TTI’s System Reliability Division, and Ginger Goodin, director of TTI’s Transportation Policy Research Center, created a handbook to help TxDOT make informed planning, design and operational decisions when considering managed-lanes facilities.
“TxDOT uses the handbook to help plan system changes that take into account how the existing HOV system has evolved over time into, for example, toll express lanes or high-occupancy toll lanes,” says Kuhn. “It was the first of its kind nationwide and really presented TxDOT as a national leader on the topic.”
Building Our Roadways to Last Longer
Roadway maintenance is another area in which TTI has provided vital assistance to TxDOT in refining and improving departmental practices. Since 2010, Texas has seen another huge population boom, and as usual, more people mean more cars using Texas roadways. And that means a greater need for roadway maintenance.
Much of the interstate system was built over 60 years ago and built to last for 30 years. “A lot of it is worn out,” explains Tom Scullion, manager of TTI’s Flexible Pavements Program. “There’s growing interest in pavement rehabilitation and developing new materials and tools to address issues associated with pavement failure.”
For 25 years, TTI researchers have developed, tested and implemented advanced nondestructive testing technologies for TxDOT to use when diagnosing the cause of pavement failures and when selecting the optimal road repair and maintenance strategies.
“We’ve been perfecting the application of ground-penetrating radar [GPR] and deflection technologies for pavement evaluation since 1990,” Scullion says. “TxDOT has implemented our recommendations and saved taxpayers a lot of money that otherwise would’ve been spent on more expensive maintenance techniques.”
Recently, TTI worked with TxDOT on a 7-mile stretch of I-20 to evaluate necessary roadway repairs. Using three existing technologies — GPR, core samples and rolling deflectometer — in a new approach pioneered by Scullion, TxDOT was able to reduce maintenance costs while achieving a better, longer-lasting pavement section.
“The I-20 project is a great example of how the TTI-TxDOT association works together,” says TxDOT Materials and Pavement Engineer Miles Garrison. “TTI’s use of the latest technology to determine the most cost-effective strategy for repairs and rehabilitation of the interstate has saved approximately $1 million to date.”