Fairfield County

I-95 enters Connecticut at its crossing of the Byram River in the town of Greenwich in Fairfield County, where the highway continues southwest into New York as the New England Thruway. Upon entering Connecticut, the highway is a six-lane freeway known as the Connecticut Turnpike. The road is paralleled by Metro-North Railroad's New Haven Line to the northwest, which also carries Amtrak's Northeast Corridor, which it follows for much of its length throughout the state. I-95 heads northeast, passing through the affluent suburban development of the Gold Coast of southwestern Fairfield County and reaching a weigh station in the northbound direction, before turning east-northeast and passing south of downtown Greenwich. The road then heads into the neighborhood of Cos Cob before it crosses over the New Haven Line and the Mianus River, on the Mianus River Bridge. Past the river, I-95 comes to a trumpet interchange which provides access to US 1 between the neighborhoods of Riverside and Old Greenwich.^[3]

I-95 northbound in Stamford

After this interchange, the freeway enters the city of Stamford at the city's West Side. The road crosses the Rippowam River and enters the dense commercial area of Downtown Stamford, where it briefly becomes elevated and serves Route 137 near the Stamford Transportation Center. Upon leaving the downtown area, the freeway passes over the New Haven Line and crosses into the residential East Side of Stamford, where there is an interchange with US 1 that also provides access to Route 106. After this point, the southbound direction gains a fourth lane as the road enters the town of Darien, where there is a service plaza in the southbound direction. In the community of Noroton, the highway passes to the south of Noroton Heights station on the New Haven Line. Near the center of town, the southbound direction narrows to three lanes again, and I-95 has interchanges with US 1 and Route 136. Next, the freeway turns to the northeast, passing over the New Haven Line and coming to a service plaza and welcome center in the northbound direction, before reaching another interchange with US 1.^[3]

Immediately afterward, the road comes into the city of Norwalk in the neighborhood of South Norwalk. The freeway turns east-northeast and passes north of the Maritime Aquarium at Norwalk as it comes to an interchange with the southern terminus of US 7 and crosses the Danbury Branch of the New Haven Line within the interchange, before crossing the Norwalk River on the Yankee Doodle Bridge and entering East Norwalk. I-95 enters the town of Westport just prior to reaching an interchange with the southern terminus of Route 33 and Route 136. Past this interchange, the freeway proceeds to cross over the Saugatuck River and continues to an interchange with the Sherwood Island Connector, which provides access to US 1 and Sherwood Island State Park. The road curves through wooded residential areas, where it comes into the town of Fairfield. Here, I-95 reaches an interchange with US 1/Center Street, which serve the neighborhood of Southport, before crossing the Mill River. Passing to the north of the Fairfield Historic District, the freeway reaches a service plaza in both directions, where there also exists an interchange with Route 135, providing access to the main campus of Fairfield University. From this point, the road curves through an interchange with US 1 on the eastern edge of town.^[3]

I-95 northbound in Bridgeport

Following US 1, I-95 enters the city of Bridgeport, which is the largest city in the state. On the city's West Side, the freeway has an interchange with Route 130, where it becomes elevated and gains a fourth southbound lane, as it passes through the industrial areas of the city's southwestern neighborhoods. Within that interchange, the road also crosses the New Haven Line. Farther east, I-95 crosses over the New Haven Line again and passes to the south of downtown Bridgeport. Here, the freeway provides access to many of the city's major landmarks in the South End and downtown area and meets the combined southern termini of Route 25 and Route 8, which both head north from I-95 as a freeway. From this point, the road narrows to three lanes in the southbound direction, and comes onto to the P.T. Barnum Bridge which carries it over the New Haven Line, adjacent to Bridgeport station, and the Pequonnock River. On the bridge, the northbound direction gains a fourth lane, as I-95 comes to an exit for Route 127 on Bridgeport's east side, after it passes over Route 130. I-95 reduces back to three lanes in the northbound direction, as it curves into the city's East End, where there is another interchange for Route 130. A short distance later, the freeway reaches an exit to Route 113 on the border of Stratford, providing access to Sikorsky Memorial Airport. Afterward, the road passes by downtown Stratford and heads into a commercial area, where it has an exit serving US 1 and the southern terminus of Route 110, before crossing the Housatonic River on the Moses Wheeler Bridge.^[3]

New Haven County

On the Moses Wheeler Bridge, I-95 crosses into Milford, New Haven County, where it heads into residential areas on the other side of the river. Here, the freeway has a trumpet interchange with US 1 within the village of Devon before it crosses the New Haven Line and passes south of the world headquarters of the Subway restaurant chain. The road continues northeast through wooded areas of the western part of Milford, where it reaches an exit for Route 15 (the Merritt and Wilbur Cross parkways), which is served by the Milford Parkway. The freeway curves as it passes northeast of downtown Milford and comes to a cloverleaf interchange with US 1 adjacent to Connecticut Post Mall, located at the northeastern corner of the interchange. The road heads northeast again into commercial surroundings and passes service plazas in both directions, before coming into the town of Orange, where it reaches an interchange with Marsh Hill Road. The overpass carrying Marsh Hill Road is called the Salemme Memorial Bridge, and the exit provides access to the west campus of Yale University.^[3]

I-95 northbound near the Howard Avenue Overpass in New Haven

The road passes to the northwest of the Yale University west campus as it enters the city of West Haven. Here, I-95 passes mixed areas of suburban development, where it comes to an interchange with Route 162. Through trucks to downtown West Haven must use this exit, as trucks may not use the northbound exit ramp at the next interchange, for Campbell Avenue and the southern terminus of Route 122, due to its steep incline. The road curves as it crosses the New Haven Line and the West River and comes into the city of New Haven. Immediately after crossing the river, I-95 comes to an interchange with the southern terminus of Route 10, which provides access to the Yale Bowl and connects to Route 34. From this point, the freeway heads northeast, passing New Haven Harbor in the neighborhood of Long Wharf, before reaching the large interchange complex southeast of Downtown New Haven. The complex includes an interchange with a flyover ramp to M.L.K. Jr. Boulevard serving the downtown area and Yale University, as well as the southern terminus of I-91, which heads north-northeast from I-95 toward Hartford. Past I-91, the freeway turns southeast to cross the Quinnipiac River on the Pearl Harbor Memorial Bridge, locally known as simply the "Q Bridge". On the other side of the bridge, the road heads into another area of mixed development in the Annex neighborhood. Here, I-95 has an interchange with the northern terminus of Route 337, which provides access to Tweed New Haven Airport.^[3]

Past this interchange, the freeway enters the town of East Haven, where US 1 parallels the highway on both sides as a frontage road with a full interchange, while the southbound direction widens into four lanes and northbound narrows to three lanes. Within the interchange, I-95 crosses the Northeast Corridor. A short distance later, there is a southbound exit and northbound entrance with Route 100 before the road curves east across Saltonstall Mountain and Lake Saltonstall and comes into the town of Branford. Within this area, I-95 passes through the Stewart B. McKinney National Wildlife Refuge where it comes to a northbound exit and southbound entrance with the Branford Connector, that connects to US 1, Route 142, and Route 146 near Short Beach. Just after the connector, there is a service plaza in both directions, and the freeway passes north of the center of Branford. From here, the road narrows to four lanes and continues east into more rural and wooded surroundings, coming to an interchange with US 1 on the east side of town. I-95 briefly enters a commercial area and passes north of the Stony Creek neighborhood. The freeway heads back into wooded areas as it enters the town of Guilford, where it comes to interchanges with US 1 and Route 77 north of Guilford Center. The road continues east across the East River marshlands and comes into the town of Madison. The road heads to the north of Madison Center, where it has an interchange with Route 79 with a park and ride lot in its northeastern corner. Past Route 79, I-95 passes service plazas in both directions, and reaches an interchange with the Hammonasset Connector, which provides access to Hammonasset Beach State Park. At this point, the route crosses over the Hammonasset River and leaves New Haven County.^[3]

Middlesex and New London counties

I-95 northbound at the Route 9 exit in Old Saybrook

Upon crossing the river, I-95 comes into Clinton, Middlesex County, continuing east through rural surroundings with some suburban elements. The freeway reaches an interchange with Route 81, close to the center of town adjacent to the Clinton Crossing Premium Outlets outlet mall, to the northwest of the interchange. From here, the road turns across the Menunketesuck River, after which it enters the town of Westbrook and reaches an interchange with Route 145. At this point, I-95 enters another curve before turning east again, at the interchange with Route 153 that also provides access to the Westbrook Outlets mall, just north of Westbrook Center. The freeway then reaches a pair of roadside stops, in which the northbound direction has a rest area and welcome center, and the southbound direction has access to Troop F of the Connecticut State Police, just before coming to the interchange for Route 166, where it enters the town of Old Saybrook. Within Old Saybrook, the road turns northeast and has an interchange with Route 154 northwest of Old Saybrook Center. On the east side of town, US 1 merges onto northbound I-95 and joins the route in a concurrency, as it widens to six lanes, and comes to a trumpet interchange with the southern terminus of Route 9, which heads northwest from I-95/US 1 as a freeway toward Greater Hartford. A short distance later, the two routes cross the Raymond E. Baldwin Bridge, that has a fourth southbound lane, over the Connecticut River.^[3]

I-95 at the I-395 exit at the East Lyme–Waterford town line

Upon crossing the river, I-95/US 1 comes into Old Lyme, New London County, where southbound widens to four lanes prior to crossing the bridge, and it reaches the interchange with Route 156, where US 1 exits the highway and the concurrency ends. The freeway reduces to four lanes before it crosses the Lieutenant River and heads into a heavily forested area with little development around the highway, where it crosses the Duck River before entering the town of East Lyme. I-95 immediately comes to a trumpet interchange with the Rocky Neck Connector, providing access to Rocky Neck State Park. Continuing northeast through the center of East Lyme, the freeway enters into areas of mixed development with suburban elements before reaching an interchange with Route 161 in the village of Flanders. Shortly afterward, there is an interchange with US 1, and the highway crosses the Niantic River before meeting the southern terminus of I-395. Here, the Connecticut Turnpike splits to the northeast along I-395, which heads toward Norwich.^[3]

Past I-395, the freeway becomes the Jewish War Veterans Memorial Highway and enters the town of Waterford. A short distance later, the road heads into suburban-like commercial areas. I-95 has an interchange with Route 85 before entering the city of New London as it gains a third northbound lane and a frontage road. Running north of the downtown area and the New London Waterfront District, the freeway meets the southern terminus of Route 32. Past this interchange, US 1 merges onto northbound I-95, and the two routes turn east to run concurrent across the 10-lane Gold Star Memorial Bridge over the Thames River, where the highways come into the town of Groton. Before the end of the bridge, US 1 exits the highway, providing access to downtown Groton. The freeway narrows to six lanes as it reaches an interchange with the southern terminus of Route 12 and the western terminus of Route 184, which also provides access via Route 12 to the Naval Submarine Base New London. A short distance later, the road curves through a directional interchange with the northern terminus of Route 349, which spurs into downtown Groton. Past Route 349, the median widens, after many miles of having a Jersey barrier in the middle of the highway, and it heads into forested surroundings and crosses the Groton Reservoir. In the eastern part of Groton, I-95 has an interchange with Route 117, leading south to the village of Noank and north to the town of Ledyard. From here, the freeway passes a northbound scenic overlook and crosses the Mystic River.^[3]

Panoramic view from the Jerome Hoxie Scenic Overlook, March 2006

Upon crossing the river, the road enters the town of Stonington, where it comes to an interchange with Route 27 within the village of Mystic, that provides access to Mystic Seaport, the Olde Mistick Village shopping mall, and Mystic Aquarium. At this point, I-95 reduces to four lanes, turns northeast past wooded areas with some residences, and comes to an interchange for Route 234 north of the center of Stonington, with a park-and-ride lot being located in the northwest corner of the interchange. From here, the freeway continues northeast to an interchange for Route 2/Route 49, providing access to the village of Pawcatuck to the south and a park and ride lot to the north in the middle of the interchange. Also, within the interchange, the southbound direction has a rest area and welcome center and the road comes into the town of North Stonington. I-95 continues to its last exit in Connecticut, the interchange with Route 216 and the eastern terminus of Route 184, as the median narrows. Immediately after this interchange, the freeway leaves Connecticut and continues as a four-lane freeway northeast into Rhode Island toward Providence.^[3]

Disasters

In January 1983, a truck with a brake failure slammed into a line of cars waiting to pay a toll on I-95 in Stratford; seven people were killed. This accident helped lead to the removal of toll barriers throughout Connecticut, which was completed six years after.

On the morning of June 28, 1983, a 100-foot (30 m) section of the Mianus River Bridge in Cos Cob collapsed, plunging northbound I-95 traffic into the Mianus River below, killing three. The collapse was blamed on the failure of the steel pins to hold the horizontal beams together and inadequate inspection prior to the collapse. Northbound traffic was diverted on this section of I-95 for 25 days. Southbound traffic was unaffected.

On March 26, 2004, a bridge on I-95 in Bridgeport was partly melted by the explosion of a tanker truck carrying over 11,900 US gallons (45,000 L; 9,900 imp gal) of fuel oil. Repairs were estimated to take at least two weeks, but the highway was opened to northbound traffic in only a few days. Southbound traffic resumed about a week later after a temporary bridge was installed to carry traffic while the destroyed bridge was rebuilt.

At 10:20 am on November 2, 2007, a tanker truck carrying heating oil plowed over the divider, knocking the side of a tractor trailer and striking several other cars in its path. Three people were killed, including the driver of the tanker and the occupants of two cars that were completely destroyed in the crash. The driver of the tractor trailer survived (his canine companion emerged completely unharmed) but the trailer was split open. At least three other cars were involved in this accident. A part of the road was damaged and took until the next morning to fully reopen, partly due to a cleanup after the accident.

Construction plans

While the corridor was designated "High Priority Corridor 65" in 2005, work along I-95 in Connecticut has been ongoing for nearly 30 years.

Interstate upgrades include:

• Replace the bridge over the Connecticut River in Old Saybrook (completed in 1993)
• Replace the bridge over the Saugatuck River in Westport (completed in 2001)
• Widening and reconstruction of I-95 through Bridgeport (completed in 2006)
• Upgrade the median divider from New York state line to Waterford to meet current safety standards (segmented construction ongoing since 1993)
• Construction of a new extradosed Q Bridge (Pearl Harbor Memorial Bridge) over the Quinnipiac River (completed in 2015)
• Reconfiguring the interchange between I-91, I-95, and Route 34 in New Haven (completed in 2016)
• Replace bridge over the West River in New Haven (completed in June 2018). Exit 44, southbound, was closed in April 2015, and the remaining ramps at exit 45, northbound, and southbound were realigned and renumbered exit 44.
• Reconstruct I-95/I-395 interchange in Waterford to accommodate proposed Route 11 expressway connection (proposed).
• Replacement of the Moses Wheeler Bridge over the Housatonic River (completed in 2016)
• Widening and reconstruction of I-95 between Norwalk and Stamford—in December 2007, a 15-month, $5.5-million (equivalent to $7.52 million in 2022^[5]) project was completed to add fourth (or "operational") lanes in each direction between the entrances and exits at exits 10 and 11 in Darien. This project was completed in 2007. A similar project between exits 11 and 13 began in 2008 and was completed in 2010. An earlier project added a fourth lane on the southbound side from the entrance at exit 10 to exit 8. After that lane was added, a CTDOT study concluded that accidents were down on that stretch of the highway by 20 percent, amounting to about 160 fewer accidents per year.^[6]
• Add southbound offramp and northbound onramp at exit 33 in Stratford (completed in 2021 and 2022)
• Widen I-95 mainline from Branford to the Rhode Island state line (proposed)
• Adding an operational lane between exits 14 and 15 in Norwalk (completed in 2016)

Fairfield Service Plaza (Southbound) in 2018

• From 2011 to 2015, all 10 of the service plazas along I-95 were rebuilt (pairs of plazas are located in Darien, Fairfield, Milford, Branford, and Madison, with a separate plaza for each direction of I-95). All of the renovated plazas feature modernized Mobil gas stations, Alltown convenience stores, Dunkin' Donuts, and Subway shops. McDonald's is also available at eight of the 10 plazas, while the largest plazas additionally feature Sbarro, Panda Express, and various other quick-service options. The last of the plazas to be rebuilt, southbound in Madison, opened in August 2015.

Mass transit upgrade projects have been undertaken in large part to reduce traffic on the highway, which is often congested, particularly in Fairfield County:

• New train station near the Fairfield–Bridgeport city line (completed in 2011, fully operational in January 2012)
• Intermodal Transportation Center in Bridgeport (completed)
• New train station in West Haven (completed)
• Upgrade catenary power lines along the New Haven Line (underway through the 2010s)
• New train station in Madison (completed)
• Purchase new railroad cars and refurbish existing cars to increase capacity and reliability
• Construct new container barge ports at Bridgeport and New Haven
• Expansion of freight service on the New Haven Line
• Replace outdated bridges and straighten various sections of the New Haven Line to allow higher operating speeds for Amtrak and Metro-North trains