Most Consecutive Suffixed Exits

[webny99]

Pretty straightforward question here: what is the longest stretch of consecutive exits with suffixes (A/B/C/D, or N/S/E/W if that's what your state/region uses)?

If one direction of a freeway breaks the chain by only having a single exit for a given number, the other direction can still count for this thread. Exit XX followed by XXA (such as 48 and 48A on the Thruway) can also count.

The longest I can think of off hand is 3 suffixed exits (6 total exit ramps):
I-490 WB: 7A-B, 9A-B, 10A-B
I-390 SB: 16A-B, 15A-B, 14A-B (sadly, 13 breaks the chain, as 12 is also A-B)
I-90 WB: 52E-W, 51E-W, 50/50A

[hotdogPi]

MA 24: 6 suffixed exits, 12 ramps. 28A-B, 31A-B, 33A-B, 35A-B, 38A-B, 41A-B. All are cloverleaves except for its northern terminus.

[SkyPesos]

I-94 IL: 43A-D, 44A-B, 45A-C, 46A-B, 47A-B, 48A-B, 49A-B, 50A-B, 51A-J, 52A-C, 53A-C
I-64 MO: 31A-B, 33A-C, 34A-B, 36A-C, 37A-B, 38A-C, 39B-C, 40A-B

[vdeane]

Pretty straightforward question here: what is the longest stretch of consecutive exits with suffixes (A/B/C/D, or N/S/E/W if that's what your state/region uses)?

If one direction of a freeway breaks the chain by only having a single exit for a given number, the other direction can still count for this thread. Exit XX followed by XXA (such as 48 and 48A on the Thruway) can also count.

The longest I can think of off hand is 3 suffixed exits (6 total exit ramps):
I-490 WB: 7A-B, 9A-B, 10A-B
I-390 SB: 16A-B, 15A-B, 14A-B (sadly, 13 breaks the chain, as 12 is also A-B)
I-90 WB: 52E-W, 51E-W, 50/50A

If 50/50A counts, then shouldn't 52E-W/52A also count?  And don't forget that I-490 has 11A-B WB (but also exit 8).

The Southern State Parkway gets impressive with suffixes; at one point there's 27S-N, 28S-N, 28AS-N, 29S-N (WB), and 30S-N.

I-95 gets impressive, though how impressive depends on how mile-based numbers are evaluated.  NB, it has 1A, 1B, 1C-D, 2A, 2B, 4A (no 3 in this direction), 4B, 5A, 5B, 6A-B, 7C (probably should break, 7A and 7B are SB only), and 8B-C before the sequential numbers on the New England Thruway take over.

[webny99]

If 50/50A counts, then shouldn't 52E-W/52A also count?  And don't forget that I-490 has 11A-B WB (but also exit 8).

Whoops, that is correct. Remembered the William St. exit but forgot it didn't have its own number.
As for I-490, Exit 10 also breaks the WB chain.

I-95 gets impressive, though how impressive depends on how mile-based numbers are evaluated.  NB, it has 1A, 1B, 1C-D, 2A, 2B, 4A (no 3 in this direction), 4B, 5A, 5B, 6A-B, 7C (probably should break, 7A and 7B are SB only), and 8B-C before the sequential numbers on the New England Thruway take over.

I'm willing to count 7C since it does have a suffix, even if A/B don't exist in that direction. With my comment in the OP, I was mostly referring to cases like I-390 at Exit 15, which has A/B southbound but no suffixes northbound.

[KCRoadFan]

The "Alphabet Loop" in downtown KC - Exits 2A through 2Y! Need I say more?

[SkyPesos]

The "Alphabet Loop" in downtown KC - Exits 2A through 2Y! Need I say more?

That's not what the OP asked for. Check examples above.

Though so far, it seems like the winner for this thread is I-94 in Chicago.

[US 89]

Unless I'm missing something obvious, Utah only has one instance of even two consecutive suffixed exit numbers - and even then only in one direction: I-215 northbound has exits 18A-B followed by 20A-B.

[ran4sh]

I-20 in Georgia would have 4 if we could count both eastbound and westbound combined.

Eastbound there is 59 A, 59 B, 60 A-B, 61 A, 61 B, which is 3 consecutive numbers.

Westbound has 61 B, 60, 59 A, 58 B, 58 A, which is 2 consecutive numbers but would be 4 if exit 60 were split into A/B.

Note that in this example, 60 A-B are opposite directions of the same crossroad, while all the others are closely spaced crossroads that each have full or partial interchanges.

It technically violates the new MUTCD to have 61 B westbound with no 61 A, but GDOT's version makes more sense because 61 B refers to the same exit either way, with 61 A being a partial exit that is missing a westbound offramp.

I-75 nb comes close and it would have 5 consecutive exits if there were multiple exits in mile 250. There are exits 248 B, 248 C, 249 B, 249 D, 250, 251 A, 251 B, 252 A, 252 B.

Edit: If we're counting ramps then it's probably I-75 SB, with 249D, 249C, 249A, 248D, 248C, 248A, with a total of 6 ramps (Each of those is a separate interchange, and not merely different directions at the same interchange.)

[webny99]

Unless I'm missing something obvious, Utah only has one instance of even two consecutive suffixed exit numbers - and even then only in one direction: I-215 northbound has exits 18A-B followed by 20A-B.

Interesting that you mention that because a lot of Utah's growth has come in recent decades, so it doesn't have many cloverleaf interchanges. Arizona is somewhat similar, except that it seems to use A-B in cases where Utah wouldn't (see I-15/I-215 vs. I-10/I-17).

[paulthemapguy]

I-55 northbound has 276A, 276B, 276C, 277A, 277B, 279A, 279B, 282A, 282B from County Line Road to IL-171.

If Illinois signed the I-55/IL-83 cloverleaf as two separate exits, instead of one exit to a C/D lane, the streak would be much longer, including the cloverleaves to the southwest at Cass Av. and Lemont Road.

[vdeane]

If 50/50A counts, then shouldn't 52E-W/52A also count?  And don't forget that I-490 has 11A-B WB (but also exit 8).

Whoops, that is correct. Remembered the William St. exit but forgot it didn't have its own number.
As for I-490, Exit 10 also breaks the WB chain.

And EB, now that I think of it.  Hasn't been A/B there in over a decade.

[JayhawkCO]

Surprisingly, the longest stretch in Colorado is not in Denver, but rather in Pueblo, with 97A&B, 98A&B, 99A&B, and 100A&B.

Chris

[webny99]

If 50/50A counts, then shouldn't 52E-W/52A also count?  And don't forget that I-490 has 11A-B WB (but also exit 8).

Whoops, that is correct. Remembered the William St. exit but forgot it didn't have its own number.
As for I-490, Exit 10 also breaks the WB chain.

And EB, now that I think of it.  Hasn't been A/B there in over a decade.

Good point. Interestingly, Google has the two exits marked as A/B, but signage rules.

[US 89]

Unless I’m missing something obvious, Utah only has one instance of even two consecutive suffixed exit numbers - and even then only in one direction: I-215 northbound has exits 18A-B followed by 20A-B.

Interesting that you mention that because a lot of Utah's growth has come in recent decades, so it doesn't have many cloverleaf interchanges. Arizona is somewhat similar, except that it seems to use A-B in cases where Utah wouldn't (see I-15/I-215 vs. I-10/I-17).

Utah is not really consistent on whether A-B suffixes should be used in cases where one ramp leaves the mainline and later splits. As you mentioned, I-215 lacks them at the south interchange with I-15 and northbound at the west interchange with I-80. Yet I-15 just had its southbound exit for the I-215 south interchange changed from 298 to 298A-B, and the interchange with US 6 and Spanish Fork's Main Street is 257A-B. Among others. One thing that does seem to be consistent is that collector-distributor ramps always get letter suffixes - see I-15's 294A-C and 305A-D as well as I-80's 115A-C.

You make a good point about cloverleaves - Utah has exactly one full cloverleaf (I-215/SR 201) and one full parclo (I-215/Redwood Rd). It does have a hell of a lot of SPUIs though.

[SkyPesos]

The suffixed exits at a ramp split on a turbine interchange, stack interchange, etc could be a thread on its own, but it seems like Missouri and Ohio have the same general stance on it. They count as a single exit, with no suffixes, so you can see two BGS installations with the same exit number because of this. But for cloverleaf ramps with a C/D lane, or pretty much anything where there's an option to return to the mainline after exiting, they use a suffix for each exit.

[Scott5114]

The "Alphabet Loop" in downtown KC - Exits 2A through 2Y! Need I say more?

That's not what the OP asked for. Check examples above.

Though so far, it seems like the winner for this thread is I-94 in Chicago.

Still, though, following I-35 through the loop gets you 1A-D, 2U-Y, 2C-F, 2H, which is 14 consecutive exit numbers with a suffix. I-70 through the loop is 2A-2E, 2G-H, 2J-M, 2P, 3A-C, 4A-C, 5A-C, 21 consecutive exit numbers with a suffix. (Some of these are partial interchanges and I'm too lazy to get pedantic with it, someone else can if they care enough.)

[ran4sh]

The "Alphabet Loop" in downtown KC - Exits 2A through 2Y! Need I say more?

That's not what the OP asked for. Check examples above.

Though so far, it seems like the winner for this thread is I-94 in Chicago.

Still, though, following I-35 through the loop gets you 1A-D, 2U-Y, 2C-F, 2H, which is 14 consecutive exit numbers with a suffix. I-70 through the loop is 2A-2E, 2G-H, 2J-M, 2P, 3A-C, 4A-C, 5A-C, 21 consecutive exit numbers with a suffix. (Some of these are partial interchanges and I'm too lazy to get pedantic with it, someone else can if they care enough.)

The way OP was counting it, it's 4 because it's the numbers 2, 3, 4, 5 each with suffixes.

[webny99]

The "Alphabet Loop" in downtown KC - Exits 2A through 2Y! Need I say more?

That's not what the OP asked for. Check examples above.

Though so far, it seems like the winner for this thread is I-94 in Chicago.

Still, though, following I-35 through the loop gets you 1A-D, 2U-Y, 2C-F, 2H, which is 14 consecutive exit numbers with a suffix. I-70 through the loop is 2A-2E, 2G-H, 2J-M, 2P, 3A-C, 4A-C, 5A-C, 21 consecutive exit numbers with a suffix. (Some of these are partial interchanges and I'm too lazy to get pedantic with it, someone else can if they care enough.)

The way OP was counting it, it's 4 because it's the numbers 2, 3, 4, 5 each with suffixes.

We can count it both ways. There will likely be a different answer for "most" depending on which way you count, which is partly why I didn't specify (and in fact encourage the style answer I used in the OP (X suffixed exits, XX total exit ramps)).

[WillWeaverRVA]

I-295 in Virginia has 11 10 consecutive suffixed exits between the I-64 interchanges, including 43A-B-C-D at I-95 and US 1.

(Exit 28 is two cloverleaf interchanges connected by C-D lanes, but the actual ramps are not lettered.)

[wanderer2575]

M-10 Lodge Freeway in Detroit.

Northbound:  4A-B-C, 5B-C, 6A, 7A-B
Southbound:  7B, 6B, 5C-A, 4C-B-A

Some exit numbering on the Lodge is really screwy, with missed and out-of-order suffices, because of a determined effort to make the exit numbers for a crossroad match on both sides of the freeway.

[webny99]

You make a good point about cloverleaves - Utah has exactly one full cloverleaf (I-215/SR 201) ...

That is unbelievable. I knew there weren't many, but that just seems crazy! Counting cloverleaf interchanges would be a chore in most states, especially east of the Mississippi.

[US 89]

You make a good point about cloverleaves - Utah has exactly one full cloverleaf (I-215/SR 201) ...

That is unbelievable. I knew there weren't many, but that just seems crazy! Counting cloverleaf interchanges would be a chore in most states, especially east of the Mississippi.

There are a couple near misses - the I-80/Bangerter interchange by the SLC airport is almost a full cloverleaf except that it has a direct left-exit ramp from the airport towards downtown. I-80/Foothill Dr in Salt Lake and I-84/US 89 near Ogden are both partial cloverleaves that probably would have been full if not for terrain factors.

There also used to be a full cloverleaf on I-15 at 31st St in Ogden. It was reconstructed into a standard diamond around 15 years ago, but you can still kind of make out where the loop ramps were on satellite imagery.

[Mapmikey]

I-295 in Virginia has 11 10 consecutive suffixed exits between the I-64 interchanges, including 43A-B-C-D at I-95 and US 1.

(Exit 28 is two cloverleaf interchanges connected by C-D lanes, but the actual ramps are not lettered.)

It used to be 15 before they built VA 895 and SR 618 interchanges.

[jp the roadgeek]

For other states with sequential exits (not including highways that have/are in the process of being converted to mileage based exits)

CT: There are no instances of consecutive suffixed exits with different numbers.  CT 15 has 67W and 67S southbound, and 68 N-E and 68W northbound, but there is no suffix on 67 northbound and 68 is skipped altogether southnound.  The only other close one is 82/82A and 84 N-E-S on I-95 in New London, but a plain 83 breaks that up.

VT: Only 3 sets of suffixed exits in the entire state, 2 of which are in the same interchange (I-89/I-91).  There may be a 4th in the future if a 2nd exit is added to I-89 Exit 12.

NH: Only suffixed exits are I-89 12A, I-93 15 E/W, the Franconia Notch Parkway (34A-34C), and Everett Turnpike Exit 5A.

DE: I-95 has 3A-3B, 4A-4B, and 5A-5B Northbound.

The Western Spur of the NJTP Southbound has 19W, 18W (the toll plaza) the famous 16W, and 15W.   If you take the northbound mainline to the Newark Bay Extension, you'd have 13-13A-14-14A-14B-14C.