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How A Single Accident Stops Downtown Dallas Traffic

Marcia Cirillo
A fatal accident Tuesday along northbound Interstate 35E near the Oak Lawn exit halted traffic on nearly every major highway near downtown Dallas.

North Texas drivers are intimately familiar with accidents slowing down the morning commute. However, Tuesday's accident on Interstate 35E was unusual.

A fatal collision between a pickup truck and an 18-wheeler blocked three lanes of traffic on Stemmons Freeway and caused a domino effect everywhere else. All traffic coming into downtown Dallas from other highways slowed to a crawl.

The cause of the accident is still under investigation, but how did one wreck stop Dallas traffic in its tracks?

It's not a mystery, one transportation official said.

Blame the Mixmaster, a group of congested, aging highways.

One spot, many highways

“Anytime you get this many highways together, it doesn’t take a whole lot for one incident to really affect traffic for quite a long time, in some cases,” said Tony Hartzel with the Texas Department of Transportation. “We have I-30, I-35E, Woodall Rodgers, and even I-345 all coming together in the downtown area.”

Hartzel says about 242,000 vehicles travel through I-35E. In comparison, about 400,000 vehicles are using the Mixmaster to get to downtown Dallas.

Ramps pose weaving woes

The multiple on- and off-ramps on the interchange also presents a problem for TxDOT.

The ramps “create a lot of ‘weaving and merging challenges,’” he said. “People [want] to get on and off the highway in a short amount of space and it does cause some fender-bender incidences.”

According to Hartzel, the Mixmaster presents one of the biggest challenges for North Texas transportation officials.

But there are other areas causing traffic headaches: I-35E and Central Expressway is one of the busiest sections of road in North Texas, as well as the High Five interchange in North Dallas.

A solution? The Horseshoe

Credit Horseshoe Project /
A look at the Horseshoe Project in Dallas, which aims to alleviate congestion near downtown.

TxDOT is replacing part of the Mixmaster with the “Horseshoe Project.” And North Texans hope that eases the traffic crunch in that part of Dallas.

The estimated $818 million project will include replacing the I-30 and I-35E bridges over the Trinity River, and creating extra lanes. It's expected to be finished in 2017. 

From the Dallas Horseshoe website:

Dubbed the “Horseshoe Project” due to its U shape, construction improvements include the expansion, repaving and addition of several new bridges and roadways along Interstates 30 and 35E; and the construction of a new signature bridge, the Margaret McDermott Bridge, over I-30.

Credit Dallas Horseshoe / TxDOT
Several changes are in the works for highways near downtown Dallas. It's part of the Horseshoe Project.

Learn more: Texas' most congested highways

Explore the Texas Department of Transportation's 100 most congested roadways in the state.Several North Texas highways are high on that list. Here are the North Texas roadways in the top 10:

4. U.S. Highway 75 between Interstate 635 and Woodall Rodgers Freeway -- Dallas County

5. Interstate 35 between State Highway 183 and Interstate 30 -- Dallas County

7. Interstate 635 between Interstate 35 and U.S. Highway 75 -- Dallas County

8. Interstate 35W between State Highway 183 and Interstate 30 -- Tarrant County

10. Interstate 35E between Interstate 635 and Loop 12 -- Dallas County

Photo credit:

Former KERA staffer Krystina Martinez was an assistant producer. She produced local content for Morning Edition and She also produced The Friday Conversation, a weekly series of conversations with North Texas newsmakers. Krystina was also the backup newscaster for the Texas Standard.
Sam Baker is KERA's senior editor and local host for Morning Edition. The native of Beaumont, Texas, also edits and produces radio commentaries and Vital Signs, a series that's part of the station's Breakthroughs initiative. He also was the longtime host of KERA 13’s Emmy Award-winning public affairs program On the Record. He also won an Emmy in 2008 for KERA’s Sharing the Power: A Voter’s Voice Special, and has earned honors from the Associated Press and the Public Radio News Directors Inc.