When first opened for public use in 1968, the then-new Mixmaster had an approximate lifespan of approximately 50-60 years, which has been extended through multiple, major rehabilitations.

Most recently, CTDOT began an intensive rehabilitation project on the interchange called the Mixmaster Rehab Project. Initiated in 2018 and scheduled for completion in March 2023 the Mixmaster Rehab Project is expected to extend the life of the Mixmaster for up to 25 years.  Learn more about the Mixmaster Rehab Project here.

Prior to the rehab project, CTDOT engaged in a widening project to ease congestion on I-84. The I-84 Widening Project was completed in 2018 and has resulted in reduced congestion east of the Mixmaster. Learn more about the I-84 Widening Project here.

The New Mix is an ongoing CTDOT program that will plan for and implement a series of projects to address the long-term needs of the Mixmaster interchange.

CTDOT, with public stakeholder input, will weigh both rehabilitation and replacement options in order to determine the best course of action for the future of the interchange.

The Mixmaster was designed to accommodate approximately 100,000 motor vehicle trips per day (predicted 1975 traffic volume). Currently, about 190,000 motor vehicle trips occur along the interchange each day. By 2045, this number is expected to approach 225,000 motor vehicle trips per day!

Reconstruction of an interchange of this magnitude, whether through replacement or an intensive rehabilitation, requires a large amount of time and advanced planning in order to properly phase and fund the program.

Therefore, the New Mix program will likely be phased with breakout projects that will occur over a number of years.  Each set of breakout projects is intended to complement and work to advance the overall New Mix program through incremental improvements.  

The potential phasing of breakout projects is described below, along with anticipated construction dates for each.

Early Action Projects

Early Action Projects will generally focus on local road and intersection improvements with the intended goal of improving the function of the overall local road network without intensive construction or construction impacts. By improving the functioning of the local road network, Early Action Projects are also intended to improve the flow of traffic in the area. As Early Action Projects are smaller in scope, they may occur relatively soon, as early as the mid-2020s.

Near-term Projects

Near-term Projects will generally occur on the outer portions of the interchange and could include improvements to entrances, exits, and lane configurations that improve the function of the existing interchange approaches but are also aligned with the goals of the future improvements to the core of the interchange. Near-term Projects will also facilitate traffic handling during the eventual core interchange reconstruction. Some, but not all, Near-term Projects will require more extensive construction and may result in impacts to drivers. Near-term Projects may begin construction in the early 2030s, before the core of the interchange is reconstructed.

Long-term Projects

Long-term Projects include significant construction work that will be required to reconstruct the core of the interchange. Long-term Projects could include replacement or reconstruction of decks, the stacked bridges, and other elements of the interchange and connections between Interstate 84 and Route 8. Construction of Long-term Projects is anticipated to begin in the vicinity of the mid-2030s to the early 2040s. 

The National Environmental Policy Act (NEPA) is federal legislation enacted in the late 1960’s that requires federal agencies evaluate the environmental impacts of their projects, including transportation projects, before they are formally implemented. NEPA also applies to any State projects that receive federal funding. The NEPA review typically begins just after the very early conceptual design process and includes the review of a range of design options.

Developed by the Federal Highway Administration (FHWA), the Planning and Environment Linkages process (PEL) considers and incorporates environmental, community, and economic goals in the very early planning and design phases of transportation projects. When PEL is used, it occurs concurrently with the early conceptual design process and NEPA occurs after PEL is complete.

When transportation projects are approached in this collaborative, multi-disciplined manner in the early planning phases, potential issues with design options are more likely to be discovered early on, and before the NEPA review.  Through the PEL process, these issues may be able to be resolved; if they cannot be resolved then those design options can be removed from consideration prior to the NEPA review.

The number of design options that are then considered during the NEPA review are both narrowed and more thoroughly vetted; therefore, the options are less likely to need to be revisited later as a result of NEPA requirements, saving both time and money.

Additionally, by including community and the economic development goals in the early planning phases of a given transportation program, PEL provides the opportunity for transportation projects to be designed in context with their environment and aligned with both community and economic development goals.

CTDOT intends to utilize the PEL approach for planning and advancing design concepts that will create a master plan vision for the New Mix.  Stakeholder groups, a Project Advisory Committee, and the general public will provide input on design and planning aspects of the project. Input and comments from all groups will be documented.

Reconstruction of an interchange of this magnitude, whether through replacement or an intensive rehabilitation, requires a large amount of time and advanced planning in order to properly phase and fund the program. Early Action and Near-term Projects, as described above, may begin to occur in the later 2020s and early 2030s, respectively.

Construction on the core of the interchange, as defined in Long-term Projects above, is not anticipated to begin for approximately 15 years. Prior to construction, there are many planning phases to be worked through, including defining a purpose and need for the project, evaluating design options, development of a final design, coordination with federal regulatory agencies, and securing necessary permitting.

Public involvement will be integral throughout the New Mix Program, including at this very early planning stage. Throughout the various planning phases for the New Mix, including PEL and NEPA which are described in FAQs above, CTDOT will provide regular updates, conduct public briefings, and invite public input.

Initial analysis has not indicated that good value can be achieved through continued rehabilitation of the Mixmaster. However, various rehabilitation and replacement alternatives will be examined more closely as part of the New Mix program’s early planning process. 

In 2018, CTDOT began to analyze whether yet another major rehabilitation project—to occur in 2045 and referred to as the 2045 Rehabilitation Analysis —would be a cost-effective way to further extend the Mixmaster’s lifespan and address functionality issues.

The 2045 Rehabilitation Analysis showed that despite a cost of approximately $1 billion (2017 dollars), another rehabilitation in 2045 would not substantially improve the interchange’s functionality, nor would it extend its lifespan significantly relative to the cost of a full replacement. There is a limit to how much the lifespan can be extended for the interchange’s steel support structures and for the decks upon which cars travel.

The 2045 Rehabilitation Analysis also found that continued rehabilitation would not be able to address operational and safety standards, which have evolved since the interchange was originally designed and constructed. These standards include roadway geometry (sight distance, sharpness of curves, and lane alignment), standard shoulders, spacing of interchanges and ramps, and left-hand entrances and exits.

In 2017 traffic volumes on the interchange stood at approximately 190,000 trips per day almost double the intended capacity of the system. By 2045, that number is expected to reach close to 225,000 vehicle trips per day. Planning for the safe maintenance of traffic flow during replacement of the stacked bridges presents another engineering challenge.

Through the New Mix Program various replacement and rehabilitation options will be considered, weighed, and analyzed against many factors including cost relative to lifespan, functionality, and safety.

There are many ways in which individuals can learn about, ask questions, stay up to date and provide input about the New Mix program.

Sign up for email updates here to receive the latest New Mix program news, notice of upcoming public meetings and more.

Additionally, you may leave comments or ask questions through the New Mix website anytime by clicking here. You can also follow us on Twitter at @NewMixWaterbury and on Facebook at @NewMixWaterbury

Structural redundancy means that the bridge’s structural system can carry loads after localized damage or the failure of one or more of its members.

Interchange is a system of interconnecting roadways that allows for traffic to travel uninterruptedly. 

System ramp a roadway that connects a “limited access” highway to another (e.g., I-84 EB to Route 8 NB).

Service ramp a roadway that connects the local roadway network to a limited access highway (i.e., on/off ramps).

Congestion is defined as the travel time or delay in excess of that which normally occurs under light or free-flow travel conditions.

Deficiency refers to a physical condition that falls below industry standards.

Future refers to the “No-Build” scenario which includes previously programmed projects/improvements.

Improve bridge conditions, extending the serviceable life of the I-84 and Route 8 Structures: new structures or reuse of existing structure(s)

Improve roadway geometry: e.g., fewer sharp curves, maintain travel speeds, and improve stopping sight distance, and shoulder widths.

Improve operations: e.g., fewer left-hand entrances/exits, improve merging distance, improve interchange spacing, and improve deficient intersections with local roadways.