• Length 232.39 miles; 97.90 miles in Connecticut
  • From I-81 in Dunmore, Pa.
  • To I-90 in Sturbridge, Mass.

Interstate 84 travels a sinuous path across the Nutmeg State, from Danbury to Union via Waterbury and Hartford, and owns some superlatives among its peers:

From the New York state line to the Connecticut River, I-84 is called the Yankee Expressway, by Special Act 166 of the 1961 General Assembly.

Interstate 84's lane configuration (discounting operational lanes, climbing lanes and short lane drops) is:

Between exits 57 (Route 15) and 59 (I-384) are four operational lanes, bringing the total to twelve -- the widest in Connecticut.

Points of Interest

I-84 has one of two double-decked sections of freeway in the state, at its interchange with Route 8 in Waterbury. This opened in 1967. The other decked freeway is Route 8, south of the same interchange. East of this, east and westbound I-84 were swapped for a fraction of a mile, where oncoming traffic was to the right. This was fixed in the 1970s.

When the topic of good highway design comes up, I-84 in West Hartford and Hartford is often brought up as a counterexample. The serpentine route has several closely-spaced interchanges, many with left exits, many of those for proposed but cancelled freeways.

The five-way "Mixmaster" interchange in East Hartford was the state's largest for decades; the honor now belongs to the four junctions fused together in Manchester, serving I-291, I-384, US 6, US 44, and Buckland Street. Collector-distributor roads tie the interchanges together, and it's actually well-designed: no left exits, and no weaving on I-84.

HOV lanes

I-84 east of Hartford has two High-Occupancy Vehicle (HOV) lanes, one in each direction. They are separated from the general-purpose lanes by striped areas (about 15 feet) and have their own entrance and exit ramps. The I-84 HOV exits are:

These lanes opened in fall 1989. The other freeway in Connecticut with HOV lanes is I-91 north of Hartford.

More information on HOV lanes: see below.

I-84 History

In December 1944, Connecticut proposed three interstate routes, which are roughly where I-84, I-91, and I-95 are now. A more specific route for I-84 was announced in December 1955. Some highways predating 1956 were incorporated into I-84 (see "Before the Interstate Era"). On August 14, 1957, the American Association of State Highway Officials (AASHO) approved the general routes for interstates 84, 91, and 95. On June 27, 1958, it approved the numbers.

The first sections of new I-84 roadway to open were in the west, near Waterbury and Danbury; a 15-mile section near Danbury opened Dec. 16, 1961. The last section of I-84 to open was the Plainville-Farmington section, on Dec. 14, 1969.

Known opening dates:

Before the Interstate Era

Traffic on US 6 and US 6A was already significant before interstate highways started opening in the late 1950s. In 1955, a new four-lane section of US 6/202 in Newtown opened, bypassing the old Church Hill Road and Glen Road routing. It's now part of I-84, which was reconstructed in the late 1960s and again in the 1970s.

In Waterbury, a section of expressway from South Elm Street toward Harpers Ferry Road opened in the late 1950s, and was open to Route 70 by 1960. The earliest part of this expressway was built in 1948.

In Hartford, planners were mapping routes for the proposed "East-West Expressway" in the 1940s; this plan became the "relocated US Route 6." Similar plans were being drawn in the Waterbury area and New Britain; much of I-84's serpentine route between Waterbury and Hartford arises from these plans.

The stone arched Bulkeley Bridge (named after former Hartford Mayor Morgan B. Bulkeley), was built in 1908, and originally charged a toll; it now carries I-84 across the Connecticut River. East of there, I-84 uses the Wilbur Cross Highway right-of-way from East Hartford to Union. The original highway, built as a narrow four and six-lane road from 1948-1954, was completely reconstructed in the 1970s and 1980s. I-84 is now 10 to 12 lanes in East Hartford, eight lanes (including HOV) to Vernon, and six lanes to the Massachusetts Turnpike in Sturbridge.

Danbury area

In 1958, Connecticut Gov. Abraham Ribicoff called building I-84 the "top priority", and work in the Danbury area began in October of that year. On Dec. 16, 1961, 15 miles of four-lane expressway were opened, from the state line to Sandy Hook. The work included the 3-way interchanges for the proposed US 7 expressway at exits 3 and 7. Opening ceremonies were held at the Lake Avenue overpass in Danbury and the US 6 overpass (exit 10) in Sandy Hook.

Beyond Sandy Hook, the highway narrowed to the undivided four-lane US 6 and 202 bypass built in the 1950s. Around 1967, this was upgraded to a divided highway, but was still substandard between exits 10 and 13, including a narrow Rochambeau Bridge over the Housatonic River, and two small interchanges (exits 11 and 12) west of the riverbank. Both the narrow profile of the highway and the short ramps of the interchanges posed safety problems.

In the early 1970s, the state conducted public hearings to improve the area. A new westbound span of the Rochambeau Bridge would be constructed, allowing six lanes of traffic over the river. Exits 11 and 12 would be eliminated, and exit 13 made safer (but now a partial interchange, only serving traffic to and from the west). Around 1976, all this was done, and a new 3-level interchange (which became exit 11) for the proposed Route 25 expressway was built. (The interchange, at the modern exit 11, currently serves two-lane Route 34 instead.) Exit 12, which served Riverside Road immediately west of the Housatonic, was deleted and not replaced.

The overlap of US 7 and I-84, from exits 3 thru 7 in Danbury, became one of the worst bottlenecks in the state in the 1980s. (US 6 and US 202 also shared the same four lanes of freeway.) Early in the decade the Housatonic Valley Council of Elected Officials (HVCEO) presented a traffic projection to DOT justifying widening the overlap to six lanes. That widening was completed in 1988.


The only double-decked section of I-84 crosses Route 8 in Waterbury, and that interchange is the focus of a multi-billion-dollar plan to reconstruct it. East of downtown Waterbury was an old, twisting, narrow four-lane freeway that was replaced in segments, starting in the early 1970s and ending in the late 2010s.

Where I-84 eastbound curves to the south, approaching Route 69, the original alignment had the eastbound lanes cross over to the left side for a short time, with some access ramps to and from Union Street. This was the only such crossover in the state, and was replaced around 1973 with a straighter, wider section: 6 lanes with C/D lanes eastbound.

Hamilton Avenue to Austin Street was the next bottleneck: a 2.7-mile stretch of 50-year-old, curving, four-lane freeway. Starting in March 2015 and ending in August 2019, the state added a lane in each direction, straightened out a curve, and relocated ramps to combine two closely-spaced interchanges. Exit 24 for Harpers Ferry Road no longer exists.

Austin Street to SR 597 in Southington was another 3.5-mile stretch of four-lane freeway, widened to six lanes in 2006. However, this project was marred by the discovery of improperly installed storm drains, catch basins, and light fixtures, as well as flaws in how they were inspected. About $22 million in additional work and repaving was required; the state sued and recovered this amount from the contractors.

Exit 26 (Route 70) was modified on the westbound side to remove the weaving caused by opposing loop ramps; it's now an asymmetric diamond interchange.

Save Exit 29!

The Southington widening project originally called for the elimination of Exit 29, a left-hand exit from I-84 westbound to Route 10 in Southington. Eliminating the ramp bridge over the eastbound lanes would have simplified the widening operation. A groundswell of local support under the "Save Exit 29" caused the DOT to change its stance in late 1998, and now "Connecticut's most-loved exit" stayed open.

Exit 29, known to the state as SR 597, was to be the north end of a Route 10 freeway to New Haven.

New Britain - Plainville

The Metacomet Ridge, a north-south line of traprock crossing the state, separates New Britain and Plainville. Both the I-84 and Route 72 expressways share the same gap in the rock (as does Route 372 and a quarry); exits 33, 34, and 35 suffer from congestion, left exits, and weaving patterns.

In December 2001, changes were made to the Crooked Street interchange area to address the problem. The entrance and exit ramps between Crooked Street and I-84/Route 72 westbound (Exit 34) were removed. In their place, a four-lane exit ramp and one-lane entrance ramp were provided for Route 372 to and from Route 72 westbound (exit 2), east of the 84/72 interchange.

Hartford Area

The canyon through downtown Hartford used to be a nightmare: three exits and two entrances in 0.2 miles. There was also no direct connection from 84 east to I-91 north, or I-91 north to I-84 west. The misdesign may have had a long heritage: a September 1948 Bureau of Highway Planning document is titled "An appraisal of two proposals for the treatment of the Riverfront Boulevard - North Meadows Highway [now I-91] intersection with the East-West Expressway [now I-84] in the city of Hartford." The question on many drivers' lips would be "what about the one they didn't pick?"

Contracts were awarded in September 1957 for the interchange work. Construction was well along by 1961.

A Hartford radio station once ran a fake promo ad for a demolition derby on the "Morgan Street Offramp" -- the congested city street drivers from eastbound I-84 to northbound I-91 were forced to crawl along. The nearby Whitehead Highway (to be I-484) was intended to carry 84-91 traffic, but was never completed. At least once this intersection gained notoriety in a car magazine as the worst place to drive in the U.S.

Starting in 1987, several ramps were moved or deleted, and on October 11, 1990, a direct flyover ramp, rising 80 feet above Morgan Street, opened to provide freeway-to-freeway access.

The interchange enhancement, part of 11 years of roadwork in the area, also involved relocating the southbound lanes of I-91 two levels down and rebuilding the Founders Bridge.

Slouching Toward Providence

I-84's intended east end has been changed twice, from the Mass Pike (I-90, Sturbridge) to Providence and back. In late 1968, the FHWA approved a new Interstate connection from Hartford to Providence. For a short time the proposed highway was called I-82, but in 1969 became part of a rerouted I-84. The existing section of I-84 from Manchester to I-90 was redesignated I-86 (see map).

In 1970 and 1971, Connecticut built two isolated sections of the eastern I-84, in Manchester and Willimantic. Both were signed I-84. However, in 1982 Rhode Island canceled its portion of the highway, citing concerns over the Scituate reservoir, Providence's main fresh water supply. In August 1983, Connecticut canceled its portion, and the I-84 to I-86 numbering was rolled back. The section of I-84 in Manchester became I-384, and the Willimantic section became part of US 6. This was made official on Dec. 12, 1984.

Around the year 2000, the state was advocating an 11-mile freeway built between those two sections, from Bolton to Willimantic. This would take traffic from the winding, 2-lane "Suicide 6" (US 6) connecting the towns. However, that effort is moribund.

For more on the history of I-84 eastward, see Hartford to Providence.

In the Northeast

The portion of I-84 between East Hartford and the Massachusetts state line is part of the Wilbur Cross Highway, which opened in the 1940s as a two-lane highway, and as a four-lane divided highway from 1948 through 1954. This highway was added to the state's interstate system as part of I-84 in 1958.

In the early 1960s, the state was already planning to widen this section. In 1964, federal approval was obtained to widen I-84 to ten lanes reaching Route 83 in Vernon, eight lanes to Tunnel Road, and six lanes through the Massachusetts state line.

Work on this widening began in the mid-1970s, from Union westward; new lanes were completely opened starting in 1976. Work finished around 1990 with the completion of the I-84/I-384 connector. Provisions were made in Manchester for the reconstruction for I-291, which was completed in 1994.

High-Occupancy Vehicle (HOV) lanes

The state's first HOV lanes opened on I-84 in the fall of 1989. Also known as carpool lanes, diamond lanes, or restricted lanes, they allow buses, vans, and cars with two or more passengers to bypass stalled traffic on the general purpose lanes. One HOV lane in each direction runs along I-84 between Route 2 and Vernon.

Many areas implement HOV lanes differently. On I-84, the HOV lane is to the left of the general-purpose lanes, separated by about 8 feet of asphalt painted with warning stripes. Crossing into or out of the lane is prohibited; instead, separate HOV exit and entrance ramps are provided. Westbound HOV entrances are at I-84 east of Route 83; Routes 30 and 83 (exit 64); Buckland Street, and I-384; traffic can exit at Silver Lane or merge with I-84 proper near exit 55. Eastbound traffic enters the HOV lane ahead of exit 58, or from Silver Lane; exit ramps are in the same locations as the westbound entrance ramps.

The lanes are marked with a black rectangle enclosing a white diamond. Signs over the lane, and on entrances to it, are black text on white background. Entrances to the lane call it the "Restricted Lane." Lane restrictions are in effect 24 hours a day. When the lanes opened, cars needed three riders; in 1992, the requirement was relaxed to two riders to increase usage.

In the mid-1990s, HOV lanes with the same configuration opened on I-91 between exit 33 in Hartford and exit 40 in Windsor.

In June 2001, the lanes were extended 1.5 miles westward, allowing direct HOV access to the Founders Bridge (Route 2 westbound) leading into downtown Hartford. Also, the area at I-84 and Route 15 was restriped so that motorists from the Charter Oak Bridge can enter the HOV lane. These improvements led to a 25% increase in HOV lane usage during the peak hour and a 34% increase over the peak period - a good result.

Business Loop 84

In the 1960s and 1970s, there was apparently a signed Business Loop 84 in Newtown, extending from I-84 exit 9 along Route 25 and US 6 to I-84 exit 10. There's more information at AARoads: Interstate Business Loop 84. Business loops are common in many other states, but aside from BL 84 Connecticut has never had any.

Other stuff

Oh, what else. Yeah. Connecticut had a state route 84, whose number was taken for I-84.

I-84 Future

TL;DR: the big, active proposals

Below are the proposed projects major enough to have their own websites as of March 2020:

Danbury area: long-term widening plan

The one practical route through Danbury from any direction is the shared I-84/US 7 section between Exits 3 and 7. In 1997, the state and city announced planned improvements to Exit 5 (routes 37 and 39), including turning lanes at Golden Hill Road and the ramps.

The Housatonic Valley Council of Elected Officials (HVCEO) recommended widening I-84 to eight lanes between exits 3 and 8, and six lanes out to exit 10. The highway is already six lanes between exit 10 and the Housatonic River. ConnDOT Air Impact modeling for this was completed in late 1997. The cost of widening was estimated at $68 million.

In mid-2000, ConnDOT announced a $260 million, nearly 20-year plan to upgrade I-84 between the state line and the Housatonic River. However, the DOT commissioner noted that the strong local support for the improvements might help shorten the schedule to 12 years or so.

In the DOT plan, a lane would be added in each direction, leaving I-84 at eight lanes from the border to exit 7, and six lanes to the river (roughly equivalent to the HVCEO recommendation). In the short term, exit ramps and merging lanes would be lengthened. In the long term, almost every interchange would be reconfigured.

Some of the interchange modifications are:

In October 2000, the state released the Final Report of the I-84 Corridor Deficiencies/Needs Study, outlining proposed improvements between the New York state line and exit 11 (Route 34). The report retained the recommendation to add a travel lane in each direction, and estimated the cost of all work at $300 million. Given the recent economic slowdown, the probability of this coming to fruition is uncertain.

In 2015, the DOT announced the 30-year "Let's Go CT" plan, which includes adding a lane on I-84 in each direction between the New York state line and Waterbury.

The active project site, i84danbury.com, does not explicitly mention adding through lanes but does list adding capacity as a goal. Timeline for construction might be late 2020s.

Southbury - Waterbury: studies, widening

The segment of Interstate 84 between Exit 13 (River Road, Southbury) and Exit 18 (Chase Parkway / W. Main St, Waterbury) is four lanes wide with deficiencies at some interchanges. A joint ConnDOT/Council of Governments of Central Naugatuck Valley (COGCNV) study completed mid-2001 recommends widening to six lanes and improving interchanges and nearby roadways, especially Exit 17 (Route 63) and Exit 18. The Route 8 interchange will be studied further.

The problem with Exit 17: the partial interchange offers service only to and from the west. Traffic from Waterbury has to use Exit 18, which adds congestion to the Routes 63/64 intersection. The region has studied this problem in the past, even recommending a bypass and interchange for Route 64 at Route 63.

Public information meetings were held June 6 and 7, 2001, in Southbury and Waterbury.

On July 19, 2000, ConnDOT conducted a public information meeting for a related Transportation Needs Study for I-84 between exits 13 (Southbury) and 23 (Waterbury).

The four issues under study were: I-84 mainline operations and capacity; interchange safety; feasibility of eliminating some closely spaced interchanges; arterial street connections; and provision for future growth.

Wilbur Smith and Associates (WSA) investigated ways to solve these problems. Under particular scrutiny were bridges and interchanges, especially the junction with Route 8; in WSA's words, " The entire interchange, with multiple left side on and off ramps and limited through lanes, is operationally deficient." (See my photos and map scans of the interchange.)

Waterbury: replace "Mixmaster" at Route 8

The 4-level interchange with Route 8 is unique, more than 50 years old, and in need of replacement. See CT 8 / I-84 Interchange for details.

Plainville-New Britain: interchange revision

Connecticut received $2.8 million in TEA-21 funding to revise the left-hand exit ramp from I-84 east to Route 72 west (exit 33) in Plainville. Before the update, I-84 was six lanes south of Route 72, but only four lanes through the exit 33 interchange. The left lane on I-84 eastbound became an "exit only lane", a nasty surprise for unfamiliar drivers. The project provided six lanes through the interchange, removing lane drops in each direction. The $20 million project was advertised for bid in August 1999, started Nov. 22, 1999, and finished around fall 2000. (Around 2003, the state also added a third thru lane in the westbound direction.)

On Oct. 5, 1999, ConnDOT announced it would add an entrance ramp from Crooked Street to I-84 eastbound in Plainville, pleasing many residents who didn't have a reasonable way to get on otherwise. The choices were: backtrack to Route 177 and get on Route 72; go forward on Route 372 to Route 72 in New Britain and backtrack; or take local streets to the Slater Rd connector at exit 36.

West Hartford

In April 1998, the state decided against widening I-84 west of Hartford to 8 general-purpose lanes, in favor of one of the following: HOV lanes; light rail in the median; light rail along other rail lines; bus-only roads. The problem area is between Hartford and Plainville, where about 105,000 vehicles use I-84 each day.

In late 1998, the DOT proposed a busway -- a separate roadway for bus-only traffic, like light rail but with rubber-tired buses. The busway would be cheaper than light rail, and much cheaper than adding lanes to I-84. It would be more flexible than rail as well, since buses could leave the busway and enter city streets. Thirteen stops were planned on the route, which would follow existing rail lines from Union Station in Hartford to New Britain. The busway opened in 2015.

In March 1999, the Capitol Region Council of Governments voted to start a $233 million transportation improvement plan. The Hartford West Major Investment Study proposes improving several I-84 interchanges (Routes 4, 6, and 9), adding auxiliary lanes near Route 173, and adding the aforementioned busway.

In August 1999, the state completed the Final Report for the Hartford West Major Investment Study. Among the proposals were the busway, and improvements to several I-84 interchanges.

Other road improvements planned include: eliminate left exit and entrance ramps at Route 4; provide for direct access between Routes 4 and 9; make exit 45 (Flatbush Ave, SR 504) a full interchange and move left exit ramps to the right; and add auxiliary lanes at several locations in West Hartford.

In late 2000 and early 2001, the state was conducting a study of the interchanges at Prospect Street, Flatbush Avenue, Sisson Avenue, and Sigourney Street. The goals were to increase access, decrease the "footprint" of the interchanges, and improve safety.

The preferred alternatives: creating a modified full diamond interchange at Flatbush (exit 45, SR 504), which would change from a cancelled freeway stub to a surface arterial; and a Single-Point Urban Interchange (SPUI) at Sisson Ave (exit 46, SR 503), after tearing down the three-level interchange there. Left exits would be eliminated, and access to area streets made easier.

Hartford - East Hartford

Improvements are planned to the "Mixmaster" interchange with Route 2. The plan: add a lane on I-84 east from the Bulkeley Bridge to Route 2, close the loop ramp from US 5 north (Main St) to I-84 west, and close the East River Drive on-ramp to I-84/Route 2. This is to lower complexity and increase safety.

In summer 1999, work began on the HOV lane extension (see above) and other improvements near Route 2. I-84 westbound would get an extra lane between exit 54 (Route 2 west, Founders Bridge) and the Bulkeley Bridge, and the exit 53 ramp would be revised. Work on the HOV lane extension completed in June 2001.

Silver Lane and Roberts Street

Exit 58, for Silver Lane (SR 502) and Roberts Street (SR 518), serves the Pratt & Whitney complex as well as retail and entertainment venues. Traffic has always been heavy there; even with the decline in Pratt & Whitney employment, the new UConn football stadium has prompted planners to dust off old plans for a grade separation at Roberts St and Silver Lane. A new addition is a proposed flyover ramp from I-84 above Silver Lane to the stadium site at the former Rentschler Airport.

East Hartford city officials generally concede the stadium alone won't generate enough traffic to justify the flyover, but future office and retail development could.

Manchester - Vernon

In March 2002, the state proposed adding an operational lane, about 3100 feet long, on I-84 eastbound between the Route 30/83 interchanges. The highway would then have five eastbound lanes (one HOV, three general-purpose, one auxiliary) between exits 63 and 64/65. Also, eastbound exit 63 would be widened and lengthened. A public information meeting was held in Manchester on March 27, 2002.

Area Man proposes "Little Dig" for Hartford

Boston underwent a huge "Big Dig" project to move a section of urban elevated highway underground. Hartford did something like this in the 1990s, lowering I-91 southbound two levels and building a promenade for unblocked, unshadowed pedestrian access to the river and East Hartford.

Musician Bill Mocarsky of Manchester saw the tangle of ramps at I-84 exit 48 (Capitol Ave) and envisioned the potential of linking Bushnell Park back to the neighborhoods north of I-84. In a conversation with the Hartford Courant, he described how I-84 eastbound, which was elevated only to accommodate a proposed interchange with never-built I-484, could be moved back beneath Broad Street, and pedestrian walkways placed above.

DOT officials note that such a project would be a long way off: even approved projects, such as modifying exits 45 and 46 on I-84, don't have funding yet.

I-84 Quotes

Enough people have chimed in about I-84 that the quotes now occupy their own page. So hit that link.

I-84 Sources