Why is the I-75/I-24 split so bad?

The Interstate 75/Interstate 24 interchange in the early 1960s. It was completed before I-24 West connected to Belvoir Avenue heading toward Chattanooga.

Glad you asked this. (William here, by the way.) When I moved to Chattanooga a year ago, I was truly baffled by the route into town. A slow-moving convoy of brake lights led north as traffic jostled for position on the ramp from Interstate 75 to Interstate 24. “Why?” was a repeated refrain in my head as the two-lane exit dwindled to one. “Who did this?”

For this question, I looked through newspaper archives and TDOT documents going back to the 1960s. I got some answers — although they weren’t especially satisfying — but was pleased to find out there’s hope on the horizon.

While the split may seem like poor road design, it created less of a traffic headache when state and local officials opened the interchange in 1961. Back then, there were only 1.7 million licensed drivers in the State of Tennessee compared to more than 5 million roaming Tennessee’s highways and byways today.

Fast forward 60 years to when the state completed phase one of a two-part reconstruction project. Despite how it may feel, traffic flow at the I-75 to I-24 split has actually improved. According to the American Transportation Research Institute (ATRI), construction projects from 2019-2021 boosted average vehicle speeds by 12% through the interchange (up to 52 MPH on average) in 2022.

Now, the split is ranked No. 59 on the ATRI’s list of the country’s 100-worst trucking bottlenecks. While that’s not a badge of honor, it’s a far cry from the 7th-worst spot the split earned amid construction in 2021.

Major construction on I-75/I-24 overseen by TDOT is set to continue this fall, and phase two makes big promises. Plans call for three-lane on-ramps from both I-75 North and I-75 South to I-24 West, effectively doubling the size of I-24 W at the split. I-24 in both directions will grow to four lanes, and I-75 N toward East Brainerd Road will expand as well.

TDOT expects the full expansion to wrap up by late 2025 and ultimately free up the bottleneck for good.

Email william@chattamatters.com with any additional questions about the split or anything else in Chattanooga.