This page covers a lot of information on an esoteric topic: exit numbering in Connecticut. If this interests you, welcome to the club. Despite its small size, Connecticut has over 400 numbered exits on 19 expressways; there's plenty here to examine and boggle at.
Like many other aspects of the state's highway system, exit numbering has been called bizarre, braindead, amusing, and other less polite names. However, there were solid reasons for most of the decisions made. As standards and plans change over the years, the highway department is often left with the choice of large-scale, conspicuous rework, or leaving large-scale inconsistencies in place.
Here, we'll cover several topics: Sequential vs. milepost-based numbering; history of exit numbers; which highways are exit-numbered; and oddities in the numbering system.
Some of the details below are best verified by driving by them: not an easy task for me, since I live in California. Because of this, I very much appreciate the efforts of Edward Hennessy, Matt Putzel, Dan "SPUI" Moraseski, Neil Kelly, and Peter Deschenes, who emailed me with additions and corrections.
Most U. S. states use milepost-based exit numbering (including California, who is just getting started). A few, including Connecticut, use sequential numbering.
Each system would treat a notional exit for Main Street in Whoville differently. In milepost-based states, Main Street might be exit 205, if it were 205 miles from mile marker zero on the highway. In Connecticut, it might be Exit 23, if it were the 23rd exit from the start of the highway or the state line.
Each system has its advocates, or defenders, depending on whose side you're on. The trend has been toward milepost-based, with Georgia recently announcing its switchover from sequential. Milepost-based numbering allows for easier addition or removal of interchanges without losing consistency, and quick arithmetic using the current milepost gives the mileage to the desired exit.
Connecticut has stuck with sequential numbering, though it almost changed this on I-91 in 1974. In general, each interchange gets one number for each intersecting freeway. Multiple offramps are suffixed with E, N, S, or W for cardinal directions, or A and B where no "eastbound/westbound" distinction applies.
Of course there are exceptions; see highway comments and oddities.
The first numbered exits in the state are found on the Merritt and Wilbur Cross Parkways. For the first several years of the Merritt's operation, interchanges were identified only by the name of the crossing street or destination. In apparent response to a number of accidents caused by motorists trying to determine which exit was theirs, the state highway commission ordered the numbering of exits effective May 3, 1947.
Exit numbers were consecutive, starting with 27 (King Street) at the New York state line. Exit 27 was chosen to continue the numbering on New York's Hutchinson River Parkway, which becomes the Merritt Parkway in Connecticut. Since then, the New York exits have been renumbered, and now go up to 30. Since the King Street interchange straddles the state line, it's exit 30 in New York (northbound), but exit 27 in Connecticut... at the actual ramps, southbound, exit 27N (in Connecticut) and 27S (in New York).
Exit numbers had no letter suffixes (A, B, E, W, etc.) at the time; the handful of cloverleaf interchanges, such as at US 7 for Norwalk, used two consecutive numbers (such as 39 and 40) for the two offramps.
Merritt Parkway exit numbers continued over the Wilbur Cross Parkway as well, ending temporarily at Exit 67 (E. Main Street, formerly US 6A) in Meriden. In 1948, Route 15 was assigned to those roads, as well as the Berlin Turnpike, Charter Oak Bridge, and Wilbur Cross Highway toward Union and Massachusetts. With the continuous Route 15 designation, a continuous exit numbering system was devised. A gap was left for a possible Parkway extension north of Meriden (which never occurred), and exit numbers started up again with Exit 85 (Route 99) in Wethersfield. The highest exit number ever in Connecticut, Exit 106, was for the Route 171 interchange on Route 15 in Union.
When I-86 was commissioned, over Route 15 from Manchester to Union (formerly part of I-84), exit numbers were left unchanged, and the nation's shortest two-digit interstate highway offered access at exits 92 through 106. When the proposal to extend I-84 to Providence was abandoned in 1983, I-84 was reassigned to that route, and the I-86 numbering removed. Along with that, exits on the route were renumbered to be consecutive with existing number on I-84. The Route 171 interchange just ahead of the Massachusetts state line, once Exit 106, is now Exit 74.
In 1974, the DOT announced a plan to renumber exits on I-91 to milepost-based, to follow FHWA standards. However, businesses along I-91 were upset about the disruption this would cause, and opposed the move. The DOT withdrew the plan on June 27, 1974.
Some expressways have exits without numbers. Most of them are short, such as the Milford Parkway (SR 796) and Route 17; the longest is Route 20, with five numberless exits.
The complete list of freeways with numberless exits: Route 3, Route 17 (both parts), Route 20, Route 78, Route 184, Route 187, Route 190, Route 349, SR 598 (Conland-Whitehead Highway), SR 796 (Milford Parkway), and US 6 in Willimantic.
Nineteen expressways do have exit numbers. Comments on each one:
Westbound in Southington, the long I-691 ramp (exit 27) diverges before the short Route 322 ramp (exit 28), making the sequence 29, 27, 28, 26. Although plans for I-291 were well known when I-84 was completed there in 1969, no exit number was reserved for the four-level stack interchange that lay unused there; when Route 9 was connected to it in 1992, the opened interchange, between exits 39 and 40, became exit 39A. A few exit numbers in the Hartford "canyon" are missing, as the area was reconstructed and several close-knit, overlapping ramps removed. Before, eastbound travelers encountered exits 49 (High St), 50 (Ann St), 51 (Trumbull Street), 52 (Morgan Street), and no number (I-91 south); now, the numbers are 49 (High and Ann), 50 (Trumbull and Main), 51 (I-91 north), and 52 (I-91 south).
In East Hartford, I-84 used Exit 58 for the Roberts Street interchange, then switched over to Route 15 numbering (see above) with exit 91 at Forbes Street. In 1985, the following exits were renumbered starting at exit 59 for I-384; the Forbes Street interchange was removed.
Westbound in Manchester, the huge collector-distributor road system at I-291 and I-384 provides one ramp for "Exit 62 & 60," US 6/44 and Buckland Street. Exit 61, Interstate 291, follows, with Exit 59 coming after.
In the I-86/Route 15 numbering era, exit 103 was missing, between exit 102 (Route 320) and Exit 104 (Route 89). I don't know why this was the case; it doesn't appear that another interchange would have been needed in that lightly populated area.
Because of a relocated Airport Road ramp and a removed Charter Oak Bridge ramp, southbound drivers encounter exits 30, 29A, 27, 28, and then 26.
When I-291 opened in Windsor, its interchange with I-91 became Exit 35A. The ConnDOT Windsor town map shows exit 35B southbound for Route 218, and Exit 35A-B for the combined northbound 218/291 exit. With interchange reconfigurations in the I-91 reconstruction near Route 20, southbound travelers now encounter exits 39 and 41 before exit 40. With the reconstruction of the Dexter Coffin Bridge over the Connecticut River circa 1990, exit 43 (Main St, Warehouse Point) was eliminated.
Exit 10 (Route 40, c. 1972) and Exit 11 (Route 22, c. 1973) were added after that section of I-91 (North Haven) opened in 1966.
In 1974, the DOT announced a plan to renumber exits on I-91 to milepost-based, to follow FHWA standards. However, businesses along I-91 were upset about the disruption this would cause, and opposed the move. The DOT withdrew the plan on June 27, 1974.
Exit 67 in Old Saybrook is actually two separate partial interchanges, at Elm Street and Route 154. The Elm Street portion was added a year or two after I-95 opened.
Where I-95 diverges from the Turnpike at East Lyme, there's a quick disconnect from Exit 76 to Exit 80. Otherwise exit numbering is conventional.
The oddity here is five unrelated exits in East Hartford numbered 5, 5A, 5B, 5C, and 5D. Exit numbers were posted along this stretch in early 1976. DOT engineer Walter Coughlin told the Hartford Courant that the planned I-86 (former I-491) connector would have displaced enough interchanges on Route 2 that they could have been numbered sequentially without letter suffixes.
I'm not sure that would have worked out. Here are the resulting exit numbers if I-86 (exit 5D) resulted in both Maple Street (exit 5C) and Griswold Street (exit 6) closing; and for good measure, Sutton Avenue (exit 5B) closing as well:
Marlborough has a missing exit: 14. Between Route 66 (exit 13) and South Main St (exit 15) is nothing meriting another interchange. I'm guessing Exit 14 could have been reserved for the proposed Route 66 freeway, a "future needs" plan of the 1960s and '70s. Though you'll see several people making this same hypothesis, don't consider it a consensus: I haven't seen an official source confirming or denying this.
In Norwich, the 2000 reconstruction of Route 2 near Fitchville led to a reconfigured interchange with Route 32 and the elimination of Exit 26, which was an at-grade intersection with Yantic Lane.
A numbering gap was left in Middletown just in case the uncontrolled-access part of Route 9 in the area was made into a freeway. According to ConnDOT town maps, the Washington Street intersection is exit 15, and the Hartford Avenue (66 east/17 north) intersection is Exit 16.
In New Britain, exit 28 (Route 72) and 28A (downtown New Britain) share the same ramp from Route 9 southbound; from 9 north, there is no exit 28A. Also, buried among the ramps in the the 9/72 interchange is left exit 27 to Chestnut Street, from 9 southbound only.
Two exits in Fairfield county were never built: exit 32 in Greenwich, and exit 43 in Westport or Fairfield. Exit 43 was reported to have been for the Sherwood Island Parkway extension, but was cancelled by protests from property owners. Between exits 42 and 44 is the longest stretch of highway in the state (5.5 miles) without an exit.
Exit 30, Butternut Hollow Road in Greenwich, existed as a grade crossing until 1955. Afterward, right turns entering the parkway were allowed, but after a number of accidents, access was closed completely.
North of I-84, Federal Road is exit 11 in both directions, and US 202 (where the US 7 expressway ends) is exit 12. The ramp to I-84 eastbound from US 7 south, however, is not exit 10, but exit 13.
Various trivia follows, discussed further in the route listings above:
"I-95: Exit 27 NB (Lafayette Blvd), Exit 27A (CT 8/25), Exit 27SB (Laf blvd)
"I-91: Exit 27NB (Brainard Road, Airport Road), Exit 28 (US 5/CT 15 South), Exit 27SB (same as above)
"I-84: Exit 27EB (I-691 east), Exit 28: CT 322, Exit 27 wb (I-691 east)
"strange, or what?"
Statewide exit numbering is a very recent innovation in California. In February 2002, the state announced it would begin numbering nearly 6,000 exits on 92 freeways. The plan is called Cal-Nexus, short for California Numbered Exit Uniform System.
Numbering is milepost-based, starting from the southern or western start of the numbered route (not just the freeway part). This is how the short CA 65 freeway near Sacramento can appear to start at Exit 307, since the start of the southern segment of 65 is that many miles south.
I wondered how some exit numbers would end up if this rigorous system were applied in Connecticut. Here are some results, which I call "CT-Nexus." Milepost is taken from the state highway log at the "center" of the interchange where the mainlines cross. Anything from milepost X.0 to X.99 belongs to exit X+1. Under this system, the state's highest exit number would be Exit 114 on US 6 in Killingly.
| Milepost | Exit # | Destination |
| 11.4 | 11A/B | I-91 |
| 13.4 | 14A | Main St., Glastonbury |
| 13.7 | 14B/C | CT 2 |
| Milepost | Exit # | Destination |
| 87.8 | 88 | CT 66, Columbia |
| 89.7 | 90 | CT 32 |
| 91.9 | 92 | CT 195 |
| 92.8 | 93 | CT 66/US 6 |
| 111.7 | 112A/B | I-395 |
| 113.4 | 114 | SR 607 (Westcott Rd) |
| Milepost | Exit # | Destination |
| 0 | 1A/B/C | I-95/South Norwalk |
| 1.2 | 2A | US 1 |
| 1.8 | 2B | CT 123 |
| 2.9 | 3A/B | CT 15, Merritt Parkway |
| 20.4 | 21 | Wooster Heights Rd. |
| 21.1 | 22A | Park Ave. |
| 21.3 | 22B/C | I-84 |
| 25.2 | 26A/B | I-84 |
| 26.5 | 27 | US 202, Federal Rd. |
| 29.9 | 30 | US 202, End US 7 Freeway |
| Milepost | Exit # | Destination |
| 27.5 | 28 | SSR 401 - Bradley Airport Connector |
| 28.4 | 29 | Hamilton Rd. South |
| 29.0 | 30 | CT 75 |
| 30.3 | 31 | Old County Rd. |
| 31.6 | 32A/B | I-91 |