Gridlock Guy: Breaking down Atlanta’s top bottlenecks

Traffic rankings are intriguing and allow us to comparatively quantify our suffering, but they are also fickle. Different weighted measurements reach different conclusions. One 2017 list ranked Atlanta’s traffic in the top 10 worst in the world. Another list that year ranked Atlanta 13th — in the U.S.

All that said, comparing consistent data from year to year does provide some insights. Once again, the American Transportation Research Institute (ATRI) has ranked several Atlanta interchanges as some of the worst in the nation.

These are technically freight bottlenecks, as the data measured comes from speed data transmitted by commercial trucks’ GPS units. But this information sheds light on the commuting experience for all motorists.

The greater Atlanta area saw two interchanges ranked in the top five in the study, four more ranked in the top 20, and another three stretches in the top 60 of the list. Let’s have a look.

I-285 at I-85 (DeKalb)

Spaghetti Junction is unsurprisingly fourth on this top 100 list. ATRI data shows the I-285/eb (Inner Loop) ramp to I-85/northbound is the slowest part of the interchange, which falls in line with what we see each afternoon in the WSB Skycopter. One reason this ramp may be slower than the rest is because I-85/northbound jams up near busy Jimmy Carter Blvd. (Exit 99). This section moved more than six percent slower than it did in 2021, falling in line with the speed decreases seen in each of the Atlanta bottlenecks on this list. The 5 p.m. hour is the slowest time of day here, and rush-hour speeds average about 28 mph.

I-20 at I-285 (Fulton)

Thankfully, this interchange is due for a rebuild in the next few years that will alleviate some of the pain. The slowest ramps in this junction are the I-20/eastbound ramp to I-285/southbound (which stays slow most daylight hours) and I-285/southbound (Outer Loop) ramp to I-20/westbound. ATRI placed this zone as the nation’s fifth-worst, though its rush hour speeds (36 mph) do not dip as low as Spaghetti Junction’s. Sections of I-20 at I-285 stay constantly below the speed limit in most daylight hours, and it moved 2.6% slower than it did the year before.

I-75 in McDonough

This area is not an interchange, but covers I-75′s intersections with Highway 20/81 (Exit 218) and Highway 155 (Exit 216) and is America’s 13th-worst. It moves 2.7% slower than a year ago. There are numerous warehouses in this area, and the trucks’ GPS tracking data shows a lot of stops around these terminals off of those two highways near McDonough. I-75 also has a sizable hill-grade here, meaning these trucks proceed more slowly, which really makes for traffic jams with regular traffic. The addition of the reversible Peach Pass/Express Lanes in 2017 have helped this area to an extent, but they would have been more effective if a permanent toll lane had been added in each direction, as opposed to the two-lane-reversal system.

I-285 at GA-400

This interchange moves 9% slower than a year ago and is the 14th-slowest nationwide. The added delays certainly are because of the Transform I-285/GA-400 project and the long-term lane reductions in three directions. The traffic is more evenly slow amongst the four main ramps in the junction, but the GA-400/southbound ramps to I-285 were the slowest. Those ramps were small, kinked, and temporary for most of 2022, and now the newer, bigger ramps to I-285 are open. During rush hour, the average speeds here are 33 mph, and interestingly, due to overnight construction lane closures, speeds in late night hours average below 55 mph.

I-20 at I-285 (DeKalb)

Just like its west-side counterpart, I-20′s meeting with I-285 on the east side is slow and is soon set for a refurb. One reason for the delays is because the I-20/westbound ramp to I-285/southbound (Outer Loop) is a 360-degree turn. That is the slowest ramp in the interchange, but the I-20/eastbound CD ramp between I-285 and Wesley Chapel Rd. (Exit 68) is similarly heavy. This junction is the 17th-worst in the U.S. and rush-hour speeds average 37 mph. This interchange is more than 10% slower than a year ago, a sharper decrease than the other Atlanta sections on the list.

I-75 at I-285 (Cobb)

As the nation’s 18th-worst, the Cobb Cloverleaf sees its heaviest delays on the I-75/southbound ramp to I-285/southbound (Outer Loop). A large amount of freight uses I-75 and 18-wheelers have to bypass Downtown Atlanta, unless they have a delivery inside I-285. This accounts for the large line of trucks (and cars) that stretch back into Marietta, as they wait for the two-lane ramps to I-285. The 2018 addition of reversible Peach Pass/Express Lanes have improved this interchange. The interchange averages 38 mph during rush hour and moves 8% slower than in 2021.

Other bottlenecks

Other sections of Atlanta freeways made the list: I-20 at I-75/85 (35th), I-75 near I-675 in Stockbridge (57th), and I-75/85 in Midtown, including parts of I-85 and I-75 north of their Brookwood merge (60th). Interestingly, the first and third of the remaining zones are inside I-285.

Many people frequent at least one of these areas. But no matter the ranking, any traffic jam feels like it is the world’s worst in that moment. The good news is that more delays actually means more business. More people are working, more goods are being delivered. So that, plus the status of being among the United States’ worst traffic zones, should be some consolation amidst the daily gridlock on our roads.

Doug Turnbull, the PM drive Skycopter anchor for Triple Team Traffic on 95.5 WSB, is the Gridlock Guy. He also hosts a traffic podcast with Smilin’ Mark McKay on wsbradio.com. Contact him at Doug.Turnbull@cmg.com.