An unused highway may reference a highway or highway ramp that was partially or fully constructed but was unused or later closed. An unused ramp can be referred to as a stub ramp, stub street, stub-out, or simply stub. The following is a list:
Interstate 291 had only approximately 3.1 miles (5.0 km) constructed based on the original 1959 plan, which is now signed Route 9. The signed portion of I-291 was not in the original plan but was added in December 1968. The original plan was to only have a western loop around Hartford, from Interstate 91 in Rocky Hill to I-91 in Windsor and be complete in 1972. The southwestern portion was met with strong opposition that cited that the study was not well researched. Before the section was cancelled in March 1979, a short stub was constructed from I-91 westward towards Route 3, including a flyover from northbound I-91. The ramp was dismantled in 1999 when I-91 was widened from 3 to 4 lanes, leaving two strips of unused pavement. [19]
Related to the Rocky Hill entry, the junction of Interstate 84 and Route 9 is a four-level stack interchange, only half of which is used. The interchange was originally built for Interstate 291. The northern half was cancelled in the early 1970s due to opposition regarding drinking water reservoirs near the proposed path. The interchange stood wholly unused for over 20 years, until Route 9 was extended in 1992 to use the south-facing part of the interchange. Route 9 ends at I-84, so the north-facing and through ramps remain unused. Viewable at [20].
Exit 45 for Route 504 on Interstate 84 is incomplete, lacking a ramp for each direction on I-84. The interchange was planned to be a short freeway, named the Cedar Ridge Connector, to the Berlin Turnpike. It has a stub exit [21], wide shoulders [22], and a large median [23].
Interstate 84 has an incomplete interchange at exit 46. It was to be for the planned Woods River Expressway and would have been designated Route 189. There are four stubs for each direction of the planned expressway to and from I-84. [24]
Exit 43 for Route 501 on Interstate 84 has a stub and a wide median near the intersection of Park Road, as it was originally planned to head farther north as the Trout Brook Connector. [25]
Route 11 has a stub continuation at its southern end. It is still alive for continuation southward to Interstate 95 at Interstate 395. [26]
Route 34 has a mile-long expressway segment, known as the Richard C. Lee highway, after the New Haven mayor who had been instrumental in the project (formerly the Oak Street Connector, where it comes off the interchange with Interstate 91 and Interstate 95. The highway ends abruptly, after only 3 exits, becoming North Frontage Road. The rest of Route 34 continues along surface streets through the city. Opened in May 1960, the plan was to have Route 34 continue as an expressway under the Air Rights Garage (which was specifically built to accommodate the highway) and along the right of way (created by relocating homes and businesses in the area when the highway was in construction from 1955 to 1960), complete with frontage roads, to Derby. Plans also existed to extend the highway to New York state or a shorter route to Route 15/Merritt Parkway existed even through the 1990s, but the project was shelved completely when the Pfizer building was built on the right of way directly past the Garage. [27] The original plan of Route 34 will never go through, but the city still desires a similar connection. The city is now in the process of demolishing the existing Route 34 Connector west of its bridge over the New Haven Railyard and replacing it with a landscaped boulevard with at-grade intersections.[28]
There is grading on the Willimantic Bypass just east of its western terminus for where the proposed Interstate 84 was to join the Bypass. A loop ramp to I-84 westbound has clearing and a dirt path for where it was to run. The I-84 mainline also has grading on eastbound US 6.
At the east end of the Bypass, there is also grading for I-84's continuation to the east towards Providence, Rhode Island.
