Engineering professors work to make state’s roads safer

Nashville should focus on eliminating weaving from HOV lanes to exits, says one engineering professor's study for TDOT.

Janel Shoun-Smith | 615.966.7078  |  01/24/2020

Tennesseans may all be driving more efficiently in the future thanks to two projects the Raymond B. Jones College of Engineering has been conducting for the Tennessee Department of Transportation since 2019.

Two engineering professors were awarded a total of $380,000 to carry out two projects designed to enhance the state’s highways: determining the efficiency and environmental impact of the High Occupancy Vehicle lanes on Interstates 24 and 65 and figuring out the best tests for TDOT to use to create a balanced asphalt mix for roadways.

These grants are two of the three pure research grants awarded to the engineering college since 2018.

Mark McDonald, professor of practice in civil engineering, and Todd Lynn, associate professor of civil and environmental engineering, worked with engineering students and other faculty from Lipscomb to analytically model the highway system and survey public attitudes about HOV lanes and current regulation and enforcement. The results of the project will contribute to making the HOV corridors more efficient, equitable and environmentally friendly.

The study, using commuter surveys, statistical modeling and microsimulation, found that “There are, unfortunately, no easy policy fixes for Nashville’s HOV corridors,” wrote McDonald. “Reverting some sections from HOV lanes to mixed flow could cause drivers to become worse off than they are now. However, at other locations, shifting traffic out of the HOV lanes via automated enforcement or pricing would worsen traffic conditions.
 
“It is my opinion that the way forward for addressing these problems should be focused on eliminating the worst weaving problems associated with the HOV lanes. If, after this problem is addressed, it would be beneficial to get more users into the HOV lane, the lane could be converted to a high occupancy and toll lane where single occupant vehicles could opt in.”

To read more on McDonald's findings about Nashville's HOV lanes click here.

In the second TDOT grant project, the professors are assessing various tests for asphalt concrete mixes. With too little binder, asphalt tends to have fatigue cracking problems, but asphalt concrete mixes with too much binder are too susceptible to permanent deformation, said Lynn.

“In this project we will be running tests on standard TDOT mixes that have been used in the field for a long time. We want to examine their standard mixes of various types so that we can understand the relationship between test results and long term performance,” said Lynn.

The engineering faculty who conduct research at Lipscomb strive to involve undergraduate students in their projects as student involvement not only attracts high-quality faculty but also potential engineering students.

“We are taking these projects on because it keeps us engaged with our professional communities, our communities need our insight into these problems, they establish the credibility of the faculty here, and it makes us more effective teachers in the classroom because we are modeling to our students the very things we do in our professional work lives,” said McDonald, professor of practice in civil engineering.

With over 20 years of experience with pavement materials testing, design, research and product development, Lynn has worked full-time in business since 2010. He holds three patents and was part of the construction team that completed the Kansas Speedway.

McDonald placed first in the Transportation Research Board’s 2004 International Competition in Long Term Pavement Performance Data Analysis. He was awarded the Dwight D. Eisenhower Graduate Fellowship in Transportation Engineering and was named the National Science Foundation’s Integrative Graduate Education and Research Traineeship fellow in reliability and risk engineering at Vanderbilt University.