The Connecticut Department of Transportation recently said it has two potential plans to replace the “Mixmaster” interchange in Waterbury, an area that has been a source of frustration for decades due of travel congestion.
The Mixmaster, an interchange where Interstate 84 and Route 8 meet in Waterbury, was planned and designed in the late 1940s through the 1950s, constructed in the 1960s, and opened for public use in 1968. Since that time, traffic has continued to increase. About 190,000 motor vehicle trips occur on the Mixmaster each day. It’s estimated that by 2045, that number will increase to 225,000.
“This highway was probably state of the art when it was designed back in the ’60s, but 60 years later, the traffic has continued to increase and the design doesn’t hold up quite as well as it did,” said Waterbury Mayor Paul Pernerewski. “This is a system that’s filled with left hand exits and on-ramps that just don’t make any sense these days with the amount of traffic.
The plans were originated through the New Mix Planning and Environmental Linkages Study. Following the study, which took place over several years, the DOT has advanced two alternatives for the interchange: the Modern Crossover Interchange and Naugatuck River Shift.
Traffic moves along I-84 in Waterbury, near its intersection with Route 8, Thursday, Aug. 28, 2025. (Aaron Flaum/Hartford Courant)
According to officials, it will be years before a final decision is made and ground breaks on one of the plans.
In the Modern Crossover Interchange option, the Route 8 structures would be reconstructed east of the Naugatuck River, “resulting in opportunities to provide access to the Naugatuck River on the west riverbank,” according to the report.
“The Naugatuck River Shift alternative would move the river toward the east to provide space for unstacking Route 8,” the report says. “The Route 8 structures would remain on the west side of the river, resulting in opportunities to provide access to the Naugatuck River on the east river bank.”
Both options would be unstacked and reconstructed with an expected lifespan of over 75 years.
“These are still conceptual, and then they’ll have to get to work on the engineering and all of the rest of it,” Pernerewski said. “I think ultimately, when the work is completed, it’s going to be a benefit to the city because the condition of the roadways will have been improved.”
Traffic moves along the bridges at the intersection of Route 8 and Interstate 84 in Waterbury, Thursday, Aug. 28, 2025. (Aaron Flaum/Hartford Courant)
Pernerewski said the topography of Waterbury near the Mixmaster, which includes a cemetery, churches and established businesses, limits possible geographical changes.
“I think ultimately it’ll benefit the city as you look at these designs. You’ve seen that a lot of the space will open up access to the river. When these highways were built, they were built along the river and they cut off river access, split the city in two, and I think these changes will help open up that access to the river.” Pernerewski said.
Pernerewski noted that traffic is “going to be a nightmare” when the work begins. He said because room is so tight, the city will not have the luxury of building the highway without interfering with everyday traffic.
“This is going to be a highway that is going to be replaced as you go along, and that is going to make getting through the city for a number of years a lot more difficult,” Pernerewski said.
The Interstate 84/Route 8 “Mixmaster” (Courtesy of the Connecticut Department of Transportation)
Last October, the DOT announced the completion of the Mixmaster rehabilitation project in Waterbury. That work was done to extend the life of the interchange before work begins on the long-term project.
“When you start looking at this, you’re talking about six years out to begin this project and then get the whole thing completed. The concept was you had to keep it going until you forget the new highway is built. And if they hadn’t done that work, it would have become dangerous,” Pernerewski said.
Department of Transportation spokesperson Josh Morgan this project has had two concurrent paths going on during the last few years.
“On one hand, we had the construction project that was out there rehabilitating those structures, making sure that they last for the next 15, 20, 25 years,” Morgan said. “On the other hand, we had a very lengthy public engagement process talking to the elected officials, business owners, community groups, residents about what they want to see the future of that interchange and transportation from the Greater Waterbury area. What we had announced earlier this week are the two really large alternatives which came out of that process,” Morgan said.
Traffic moves along I-84 in Waterbury, near its intersection with Route 8, Thursday, Aug. 28, 2025. (Aaron Flaum/Hartford Courant)
Morgan said the DOT went into public hearings with no preconceived notions but soon learned that people were sick of being stuck in traffic and are tired of the crashes that are happening at the Mixmaster on a daily basis and want improved mobility choices.
“What these alternatives, do in both instances, would actually unstack those highways, untangle what really was an engineering marvel in the ’50s and ’60s, and make it more of a traditional highway that’s not going to be interconnected,” Morgan said. “It’s going to eliminate those left hand exits and left hand on-ramps, which are creating unsafe conditions.”
Morgan said the changes will positively impact local roads near the Mixmaster with improvements planned for crosswalks, sidewalks and bike lanes.
“We’re also looking at how we can improve rail travel, bus travel, giving people mobility choices. So again, it’s not just worrying about the cars and vehicles. It’s how we can connect everything together, no matter your motor travel, and how this also can tie into Waterbury’s future business and economic development goals,” Morgan said. “It’s so important that we had these conversations working hand in hand with the city, with the community.”
Traffic moves along I-84 in Waterbury, near its intersection with Route 8, Thursday, Aug. 28, 2025. (Aaron Flaum/Hartford Courant)
Morgan is quick to note that these concepts are still in the “very early stages” of planning. Morgan said there will be more public engagement, and the DOT wants to show that it is committed to these improvements.
“I don’t think there’s anything that would be more frustrating to a resident for us to go out there and spend three years planning and talking to them and then saying ‘Bye, we’ll talk to you in 20 years from now when we come back to do this project,’” Morgan said. “We’re also doing what’s called breakout projects, or early action projects, things that have already started, things that will start next year, all to improve safety, improve mobility as we get to that point in the next 10, 15 years when we start doing that major project of unstacking the Mixmaster.”
The earliest the projects would start would be in the mid 2030s, according to Morgan.
“Then how long that ultimately takes is unknown for the whole completion of the project,” he said. “But right now, we’re trying to get through this next phase.
“This is an important milestone. We’re excited that we got to this point, but certainly there is a lot of work left to do before we break ground on this large-scale project. We are really going to try to design it to minimize as much of those impacts on Route 8 and I-84 as possible,” Morgan added.
