Exit Number Suffixes: Are the Spaces Official?

[vdeane]

So as I've been working on revamping the exit lists for my website, I've been wondering how exit suffixes actually work.  The MUTCD requires that there be a space between the main part of the number and the suffix, so I've been updating my exit lists to match, but I've been realizing that I don't really like that.  I've also noticed that standard roadgeek convention for things like the wiki is still to have no space, and I've even seen DOT documentation that seems to be that way.  So the question is: if you have, for example, exit 48A, is it actually 48 A, or is that just a signage convention to make it more legible?

Similarly, there's the question of whether prefixes should have a space.  I don't think the MUTCD says anything on them, probably because they aren't very common... in fact, I'm not even sure if they exist outside of New York (and NY is pretty inconsistent on that subject; the Thruway can't even seem to decide how to do signage, with examples of both on the Berkshire Spur alone).

[LilianaUwU]

As for Québec, suffixes are mostly directions. BGSes will include a dash:

A-20 EB, sortie 311 - 1 by Liliana Vess, on Flickr

Exit gore signs spell the direction (e.g. 312 NORD and 312 SUD at that specific exit, if that exit did have exit gore signs). The only one that's not spelled out is Sortie 64-A on A-15 (Décarie) SB, which also has dashes.

[Henry]

I like it better when there's no space between the number and suffix. Same goes for when there's a dash separating the two suffixes (as in 1A-B).

[Big John]

2023 MUTCD sections 2E-23-24 show a space before the suffix.

[J N Winkler]

So as I've been working on revamping the exit lists for my website, I've been wondering how exit suffixes actually work.  The MUTCD requires that there be a space between the main part of the number and the suffix, so I've been updating my exit lists to match, but I've been realizing that I don't really like that.  I've also noticed that standard roadgeek convention for things like the wiki is still to have no space, and I've even seen DOT documentation that seems to be that way.  So the question is: if you have, for example, exit 48A, is it actually 48 A, or is that just a signage convention to make it more legible?

It's purely a signage convention.  It's similar to the requirement in Britain that there be a small amount of whitespace between the system designator and the number on signs even though both are currently written in print without any and also without any intervening punctuation.  (Usages like "A.40" and "M.1" have been obsolete for decades.)

Some Germans can be real pedants about inserting a half space between "A" and the number when talking about an Autobahn, but in my experience, actual official usage is wildly inconsistent.  In its construction contract advertisements, Die Autobahn GmbH sometimes uses a full space ("A 1") and elsewhere no whitespace at all ("A1"); I have never seen a half space.  (The actual signs don't use system designators.)

[wriddle082]

Kentucky seems to like putting a dash between the number and the suffix (or at least in the Louisville area).

https://maps.app.goo.gl/y6Zq9ocSfbku4UKV8

[pderocco]

I can see where someone with poor eyesight, glancing at a sign saying exit 7B, might read it as 78. Maybe even 7A as 74. But since my eyes are okay, I think leaving out the blank is more space efficient.

[1995hoo]

I read somewhere—it may well have been somewhere here on the forum—that the space is supposed to be something less than a full space, something closer to what typographers call a "hair space." A common use for a hair space in printed materials is with nested quotation marks placed next to each other (e.g., "My brother asked, 'Did Ovechkin score a goal last night?'") to make the adjacent single and double quotation marks a little more legible and easier to discern visually. If you're using a serif typeface with "smart quotes" ("curly" quotation marks), the marks tend to run together when adjacent like that.

When the sign uses a hair space, I think it can look decent, as with these two relatively recent signs on northbound I-395 in Virginia. The smaller space between the number and letter help to tie them together. Notice the difference in the size of the space on the exit tab compared to the one in "Edsall Rd" on the main signs.

Compare that to this monstrosity at the next exit north of there. This thing has multiple deficiencies, but for present purposes I'm focusing on the exit tab. Notice the enormous space between the "3" and the "A." I think that's hideous. This particular sign was put there sometime between 2008 and 2011, based on clicking through the old Street View images (the July 2008 has the old sign, which had an exit tab that was perhaps slightly less misaligned, though still in the wrong place).

[vdeane]

I read somewhere—it may well have been somewhere here on the forum—that the space is supposed to be something less than a full space, something closer to what typographers call a "hair space." A common use for a hair space in printed materials is with nested quotation marks placed next to each other (e.g., "My brother asked, 'Did Ovechkin score a goal last night?'") to make the adjacent single and double quotation marks a little more legible and easier to discern visually. If you're using a serif typeface with "smart quotes" ("curly" quotation marks), the marks tend to run together when adjacent like that.

Yes, I've noticed that the space on the signs is smaller than the space I type.  Based on this thread, I think I'll stop adding spaces for any new exit lists I convert, and circle back and remove the ones from the lists I already did.

Compare that to this monstrosity at the next exit north of there. This thing has multiple deficiencies, but for present purposes I'm focusing on the exit tab. Notice the enormous space between the "3" and the "A." I think that's hideous. This particular sign was put there sometime between 2008 and 2011, based on clicking through the old Street View images (the July 2008 has the old sign, which had an exit tab that was perhaps slightly less misaligned, though still in the wrong place).

Wow, that's some good quality imagery from 2008 from Google!

As for Québec, suffixes are mostly directions. BGSes will include a dash:

A-20 EB, sortie 311 - 1 by Liliana Vess, on Flickr

Exit gore signs spell the direction (e.g. 312 NORD and 312 SUD at that specific exit, if that exit did have exit gore signs). The only one that's not spelled out is Sortie 64-A on A-15 (Décarie) SB, which also has dashes.

I'd say "that would make signing spaces where you'd sign, say 'exits 314-312' for a c/d lane awkward", but I'm pretty sure MTQ's policy is "don't do that".

[roadfro]

I read somewhere—it may well have been somewhere here on the forum—that the space is supposed to be something less than a full space, something closer to what typographers call a "hair space."

Correct. Here's the relevant wording from the standard in 2009 MUTCD Sec 2E.31 (I'm replying from my phone, so can't easily sift through the 2023 PDF, but I imagine this is still there):

Suffix letters shall be used for exit numbering at a multi-exit interchange. The suffix letter shall also be included on the exit number plaque and shall be separated from the exit number by a space having a width of between 1/2 and 3/4 of the height of the suffix letter.

[kphoger]

Is this not just a matter of equivocation?

Space = A gap of any sort
Space = An inter-word separator in written language

The MUTCD is demanding the former when designing signs.  That doesn't mean it's demanding us all to use the latter when writing or typing route designations.

[hbelkins]

Kentucky seems to like putting a dash between the number and the suffix (or at least in the Louisville area).

https://maps.app.goo.gl/y6Zq9ocSfbku4UKV8

There are a handful of dashed suffices in the Louisville area. I think those signs are native to the original construction of I-265 (hence the center tabs rather than the flush-right tabs).

Then, there are these...

https://maps.app.goo.gl/fs1TGSvgkVtxPBW38

[stormwatch7721]

A few of the guide signs in Ohio still have the suffixes together.

[CtrlAltDel]

As for Québec, suffixes are mostly directions. BGSes will include a dash:

The hyphen is definitely the way to go with this, and it's what I use in my own records.

For what it's worth, I also use a hyphen to distinguish routes, such as I-25, US-25, IL-25, and so on.