When we think of a roadway, most of us think of the asphalt or concrete that we are riding on. Little thought is given to the ditches that line our roads or how the water flows off our roadways. A Texas A&M Transportation Institute (TTI) researcher has come up with an automated way of determining if those ditches are doing their job properly and safely.
The Texas Department of Transportation (TxDOT) maintains an extensive data collection documenting the performance of roadways in the state. Charles Gurganus, associate research engineer in TTI’s Pavements and Materials Division, is studying an automated method of providing TxDOT with right-of-way-line to right-of-way-line roadway surface geometric information. The project is called, “Developing a Surface Drainage Rating for Inclusion in TxDOT’s Asset Management System.”
Utilizing LIDAR (Light Detection and Ranging) technology, Gurganus can collect extensive roadway geometric data, including roadway cross slopes, super elevations, front slope steepness and drainage areas of a roadway. The technology can also determine the depth of a roadside ditch and its offset related to the nearby pavement structure. All data can be collected at highway speeds.
“It’s almost like we are proving what has always been intuitive about roadway work. We think shallow ditches close to the edge of the pavement may cause pavement problems. We think deeper ditches farther away from the pavement edge with a good longitudinal grade are more desirable. Now we can measure that at a network level and compare it to pavement performance,” Gurganus said.
The technology is a single boom-mounted laser device mounted 10 feet in the air. It also uses GPS and an inertial measurement unit plus a video camera.
Gurganus hopes to link road distress problems to the collected data. “We know this roadway is having performance problems from a distress standpoint. How does that relate to ditch depth and offset? If a roadway is performing poorly, such as alligator cracking or rutting, we can now show that it has a shallow ditch close to the pavement’s edge. If repairs are going to be made, we can deepen the ditch and move it away from the pavement. It’s a more holistic repair approach,” he said.
Data has been collected from roadways in TxDOT’s Austin, Brownwood, Bryan, Atlanta, Tyler and Corpus Christi districts. The challenge is taking that data and deriving useful information from it. In 12 miles of roadway, the system can generate 25 million points; a lot of data. As Gurganus noted, it’s “how to go from being data rich to being information rich? How do we supply the client with information-rich data that meets their needs?”
He continued, “If we can begin to integrate this information into project development, it will give TxDOT more information so that their project scopes can be more refined. This should help them stretch their funds farther and do more lane miles of work every year. Maintenance supervisors will be able to focus on problem spots with measurable data. Time, effort, materials and money will impact roads that really need it.”
You must be logged in to post a comment.