Chattanooga is home to a thriving freight and logistics industry — and two of the most bogged down intersections in the state when it comes to moving stuff by truck.

The intersection of interstates 75 and 24 and the intersection of Interstate 24 and U.S. 27 made the list of the country's 100 worst bottlenecks from the the American Transportation Research Institute, though neither of them ended up in the national top 20.

"I'm a little surprised they aren't ranked a little higher from a national scene," said Andy Vanzant, senior vice president of operations for Covenant Transport.

The two local traffic-jam magnets sit just a few miles apart, with the dreaded Ridge Cut between them, but the big picture of bottlenecks is even more daunting at the regional level. Three intersections in and around Atlanta and one in Nashville made the top 10 list of the country's worst bottlenecks.

"Chattanooga is the gateway to the Southeast, we've called it that for years and years, and with the explosion of Atlanta, it has exacerbated the truck traffic because people have to feed that demand for consumer goods" Vanzant said. "The infrastructure has not been able to keep up with the migration of Northerners moving South."

Worst bottlenecks in Tennessee The American Transportation Research Institute ranked the 100 worst freight bottleneck intersections in the country. These are the six in Tennessee that made the list and their relative score among the 100 worst congestion sites. No. 3: Nashville, I-24/I-40 at I-440 (East) No. 22: Nashville, I-40 at I-65 (East) No. 32: Chattanooga, I-75 at I-24 No. 51: Chattanooga, I-24 at US 27 No. 74: Nashville, I-65 at I-24 No. 94: Nashville, I-65 at I-440 Source: TruckingResearch.org

The bottleneck analysis synthesizes several elements, including a massive database of truck GPS data at 300 locations throughout the U.S., and an algorithm that measures the impact of congestion on truck-based freight.

Covenant has used electronic logging devices for more than 10 years to collect trip data from its trucks in real time, Vanzant said. As those devices have become more widely used across the industry, they've painted a vivid picture of the effects of rapid growth across a road infrastructure that hasn't kept pace, he said.

"Most carriers have decreased their average mile-per-hour transit times by about 5 miles per hour," he said. "If you run Louisville to Atlanta — and most every carrier runs that lane — we used to say that was an average 51 or 52 miles per hour, but now we set it at 47 mile per hour."

Staff photo by Tim Barber / Northbound Interstate 75 traffic approaching the convergence of Interstate 24 westbound, backs up far into the state of Georgia in this view from exit 1, at East Ridge, in June 2019. The American Transportation Research Institute ranked the 100 worst freight bottleneck intersections in the country, and this intersection is one of six in Tennessee that made the list.

The spot where interstates 75 and 24 part ways is undergoing a massive revamp, with a $132.6-million project under construction to improve the intersection, said Tennessee Department of Transportation spokeswoman Jennifer Flynn. In addition, the department has a project in development to widen and improve I-24 from the U.S. 27 interchange to the Georgia line, she said.

"It is early in development, but once completed, it should help traffic congestion along the I-24 corridor in the area of U.S.27," Flynn said.

TDOT is also planning a project to to modify the I-24 interchanges at Broad Street and Market Street, she said.

"The reworking of these interchanges should improve the traffic flow in that area of I-24, which is near U.S. 27," Flynn said.

Another project on U.S. 27 — a $143.2 million road construction zone through downtown Chattanooga — aims to widen and straighten the roadway's original winding path and to improve on- and off-ramps between the river and Interstate 24. The upgrade has been more costly and taken longer than expected, in part due to unexpected underground problems, and is slated for completion in October.

Worst bottlenecks in nation The intersection of I-95 and SR 4 in Fort Lee, New Jersey, is the worst freight bottleneck in the country. The rest of the Top 10 includes: No. 2: Atlanta, I-285 at I-85 (North) No. 3: Nashville, I-24/I-40 at I-440 (East) No. 4: Houston, I-45 at I-69/US 59 No. 5: Atlanta, GA, I-75 at I-285 (North) No. 6: Chicago, IL, I-290 at I-90/I-94 No. 7: Atlanta, GA: I-20 at I-285 (West) No. 8: Cincinnati, OH, I-71 at I-75 No. 9: Los Angeles, CA, SR 60 at SR 57 No. 10: Los Angeles, CA, I-710 at I-105 Source: TruckingResearch.org

"It should help congestion in the area for sure, because it will widen U.S. 27 and add frontage roads for improved traffic movement," she said. "It may not directly affect the interstate, but perhaps some traffic might choose to use U.S. 27 instead of I-24 once U.S. 27 is no longer under construction."

Vanzant said he's optimistic all the investments in road construction will ease some of the slowdowns, but he's keeping his expectations in check.

"I am optimistic about what we're doing locally, especially at the 75/24 split. But will it make it go back to what we think will be utopia? Probably not."

Contact Mary Fortune at mfortune@timesfreepress.com or 423-757-6653. Follow her on Twitter at @maryfortune.