NY - Sequential vs. Mile Based Exits

[hotdogPi]

I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

[kalvado]

I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

Just get a GPS navigator.

[cl94]

I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

Exit 2 and Exit 3 are 30 miles apart, the 7th longest gap between exits on an expressway in the US and the 5th longest on the Interstate system. Somerset-Bedford is the only longer gap in this part of the country (4th longest, ~35.5 miles). Exit 2 is 10 miles inside the state. That's not something most infrequent travelers have memorized. Hell, Exits 2 and 3 is THE prime example of why the Northeast needs distance-based numbers.

[seicer]

Not that I am against mile based exits - but there is a clear sign that indicates how far it is to the next interchange. There is also a service plaza in between. It's not as if people are going to starve.

[kalvado]

I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

Exit 2 and Exit 3 are 30 miles apart, the 7th longest gap between exits on an expressway in the US and the 5th longest on the Interstate system. Somerset-Bedford is the only longer gap in this part of the country (4th longest, ~35.5 miles). Exit 2 is 10 miles inside the state. That's not something most infrequent travelers have memorized. Hell, Exits 2 and 3 is THE prime example of why the Northeast needs distance-based numbers.

Interestingly enough, you still need a "next exit XX" sign or a good look at the map to find out where the next exit is. 
Because,  considering  our example of exit 3 being 30 miles from exit 2  being a problem: in case of renumbered highway, next exit past exit would-be-12 is possibly exit 15 or - equally possibly - exit 42. There is no clear way of knowing that without additional information, and difference between "next exit XX miles" and "next exit YY"  signs is not that great.
So no real difference in terms of relayed message in this case - unless  driver needs that specific exit 
Don't get lost in your preset agenda, look at actionable items!

[empirestate]

It would show "33" precisely because that is its signed exit number and maps undertake to display the exit numbers that are actually signed in the field.

What? No, no...we're explicitly talking about a case where the exit has no number. Let me see if I can reconstruct the quote sequence fully:

But what if the exits don't have numbers? Then there's no need to relate anything–the exit's milepost is its milepost, one and the same.

Mileage-based exits still need to be explicitly signed for map relatability, since the vast majority of maps show exit numbers but not mileposts, and mileposts are often hard to find even in online mapping services that offer driver's-eye photography of the physical roadway (like StreetView).

I'm confused about why that would be a problem. In a mile-based system, the exit's identifier is the same as its milepost; the map just shows that number, whatever it is. If the exit's identifier were not its milepost, its milepost would still be the same and the map would still show that same number. And if the identifier is a name, I suppose the map would also show the name; and you discuss that below.

Nope.  In the Verona example, the map would show "33" instead of "252."  I would then have to refer to a separate resource (such as the Thruway cross-reference) to get the milepost.

Why would it show "33"? That's its current (sequential) exit number.

It would show "33" precisely because that is its signed exit number and maps undertake to display the exit numbers that are actually signed in the field.

So you see, "33" isn't its signed exit number, because it has no exit number, and no exit number is signed in the field. There'd be no reason for a map to display "33". What the exit does have is a milepost; in this case 252. So that's what would display on the map. (The exit may or may not also have a name, which may or may not also be displayed on the map.)

But in the case where exits don't have numbers–they're named instead–the map would not show "33", it would show "Verona" (or whatever name is chosen).

It would not.  I know of no third-party commercial mapping service that shows interchange names on a single-sheet state map.  The Pennsylvania Turnpike has interchange names and I have never seen those shown in either commercial mapping or on the PennDOT official state map.

Well, you can't say it would not–it's a hypothetical and it's in the future. You can't really predict with certainty what mapmakers would do based on what they do today. But sure, let's say they do not. The point remains, they wouldn't show "33" either. If they don't show the name, the only thing left to display is the milepost; so, "252".

If the map also showed the exit's milepost, it would show "252" for that.

I know of no map that shows a milepost for an exit unless it is signed as the exit number.  For example, in Kansas non-Interstate freeways have milepointing with MUTCD-style mileposts, but because their exits are not numbered, exit mileposts are not shown on maps.

I don't know of one either, but see above. But again, sure, let's say this mapmaker decides not to show names or mileposts: in that case, it's just blank. It's definitely not "33".

The advantage of distance-based exits is that if you know the number for your desired exit, then you can refer to the last milepost passed to estimate your distance to the exit.  This is not possible with a sequential system.

Of course. And if the exit doesn't have a number, but you know its milepost, the same applies. But that's not in dispute, is it? People keep mentioning this advantage of mile-based numbering, but I'm not sure why–we all agree that it has this advantage.

The problem is simply this:  if all mapping that is easily available to the customer shows just the sequential exit number ("33" in the Verona case), then how is a customer to learn the exit milepost so that he or she can commit it to memory for purposes of distance-to-exit estimation while driving?  The advantage of distance-based exit numbering is that it relieves customers of the obligation to find and check obscure resources to convert a sequential exit number to an exit milepost.

Right, but again, we both already know that advantage exists. What you have not persuaded me of is that it's worth converting a system in order to take this advantage. You don't need to inform me what the benefit is, you need to convince me that it's consequential.

Strictly speaking, I only have to persuade a majority of New Yorkers.

A majority of New Yorkers, why? Nobody but me has put forth this viewpoint, and a couple of you decided to rebut it; so, there's nobody to persuade but me. And, certainly, you don't have to persuade me–I'm perfectly content to keep my existing viewpoint. But since you took the initiative, I'm happy to participate. (However, please don't let it get to the point where it frustrates you–I have no interest in being combative, but I do want to answer any questions you have as long as you're still unclear what my view is, or why.)

And, frankly, many of the  counterarguments to converting to mileage-based exit numbering that you have raised perplex me, not at a conceptual level but simply because they are raised at all.  How much and what type of highway travelling have you done in states that have mileage-based exit numbering?

Extensive, and in every state save one. So–again–I'm not unaware of the advantage of mile-based numbering, and I'm far from unaccustomed to using it. But why should it follow that it needs to be adopted in my state, or any other? Why must anyone who has experienced mile-based numbering insist on it everywhere?

In every case the reaction has been the same:  why are these (sequential-numbering) states still sticking to an inferior system?

Ah, but one of those cases was not me. Had it been, you'd have gotten a different reaction, as you've now been reading over these few pages.

That may very well be true.  There are nevertheless demonstrable benefits to mileage-based exit numbering versus sequential numbering.

Yes, there are. And I nevertheless do not believe they warrant a conversion in New York. Unless there's new information I haven't yet considered, I just don't know what more there is to it than that.

[empirestate]

You've got a full time job between me and JNWinkler - are you enjoying this yet? 

Well sure; shouldn't I be? I'm happy to explain why my view is what it is, and I certainly don't mind your attempt to persuade me to a different one. So far, that's been unsuccessful, but I don't in any way object to it.

Of course - I can tell I didn't expect you to have objections, I was simply noting that you're making two posts to my one.

Indeed; my work is certainly cut out for me. :-)

OK, that's fine. As I've said, if naming is excessive, then leave it at that... it doesn't represent a problem that badly needs a solution.

I've condensed what you said here, as I agree.

OK–although you do have a few words remaining on the subject:

To a certain extent, part 1 happens anyways - people will use whatever they want to refer to and identify the interchange. But I fail to see why, in any context, signage is needed specifically to aid motorists with this. It doesn't ever matter to the motorist what it's called or if it even has a name - the name is just a reference point that happens to be used, that the DOT has no obligation (or reason) to sign.

The situation that this would address is the aforementioned scenario, where duplicate interchange numbers arise along a single road or facility. Whether you feel that's "needed" or whether it "matters" is akin to my feeling of whether an exit numbering conversion is "needed" or whether it "matters" that motorists can't judge distance from the exit number alone.

Related to what I said above, the DOT's obligation is totally unrelated to part 1 - however the average person wants to refer to the interchange in non-road settings is up to them. It doesn't matter if people still call them "Circletown" and "Squaretown" - if that's what they've always been called, so be it. The DOT's responsibility with regards to signage is to aid motorists in finding, and ultimately reaching, their destination, and using names or sequential numbers are both inferior ways to achieve this objective. In the case of a double "Exit 226", the exits can still be easily distinguished, even in the case of the thruway, by specifying either a]the general area, or b]the route number.

Both parts have to do with signing and reference systems that apply to the roads overall, so they're both part of the DOT's responsibility–its area of concern. The question is whether they ought to take action on either part. You feel that they needn't address part 1, and I'm easily persuaded to accept that. Where we differ is that I feel the same about part 2 as you do about part 1: there's an action that could be taken within the DOT's bailiwick, but I feel it's unwarranted, whereas you feel it is warranted.

And yes, the double 226's would be addressed by people using the "common-law" names, in the absence of official ones.

I view part 2 as the only part that has to be addressed by the DOT. Whether or not you approve of their handling it in New York state is, by nature, a very subjective matter. I don't believe sequential numbers are any great hindrance to motorists, but using them prevents the benefits of mileage-based numbering from being unleashed. As such, in my mind it's more of an obstacle than a real problem.

We're of essentially the same mindset here. I agree that mile-based numbers would not be a hindrance; if New York had always had them, or if they were suddenly switched over magically and at no expense, I wouldn't consider it an injustice in any way.

If you don't care, that's fine; you have no reason to. But NYSDOT itself, as the true responsible party here, should definitely care enough to take the initiative; both to improve motorist guidance and to comply with the MUTCD.

It is certainly NYSDOT's business and duty to consider the issue, and certainly they should care about handling the issues on their plate. From the information I have now, I disagree that they should take any action from a purpose-and-need standpoint. I do recognize that they may need to take action for bureaucratic reasons.

Also, this thread is not specific to the thruway, but the state as a whole. Addressing a re-numbering of the thruway presents a unique set of challenges; challenges that appear larger-than-life, that are insignificant in the big picture, and that can be fairly easily overcome.

Not this entire thread (i.e., topic)–just this sub-thread regarding the renumbering of the Thruway and the confusion that could arise. My suggestion of names was specifically in response to that. And I do agree with you that the volume of discussion we've had about that over the years belies the relative unimportance of the subject. (I feel the same about Breezewood, as I mentioned over in that discussion.)

I guess what I'm saying is, I get your point, but I don't see how it applies. For part 1 (naming), why does being able to know the distance mean you can't also identify the interchange?

It doesn't, but there's no reason for signage to identify the interchange, so why should it?

OK, yeah, it's a different question. And we both accept that, perhaps, no, it should not.

You tend to view conformance as less of an issue than me. Because of this, I'll probably never convince you that it's worth the cost. I personally think it's important enough to justify the change, but a good chunk of that is just me being a roadgeek, and being nitpicky, and having an appreciation for consistency.

Oh, I definitely appreciate those qualities–in fact, I'm a bit surprised at myself for being willing to accept deviations from orderly systems, such as sequential numbering and Breezewood. (I'm less accepting of Interstate numbering violations, but not debilitatingly so.) But what I've realized over the years is that conformity is lifeless without variation. Like yin without yang, a rule without exception is an incomplete cosmos.

Motorists shouldn't need additional help to find their destination, but not everyone has the knowledge that you and I have. It's only acceptable that the DOT should provide that additional information when possible (and when it doesn't hinder the message being conveyed - which it doesn't, as we've established). Though it may not be true in either of our cases specifically, it's not incorrect to say the vast majority of motorists can't calculate the distance to their exit on their own based on head knowledge, nor can they do so with the combination of head knowledge and a sequential number.

All of this I consider to be adequately addressed by modern navigation systems.

And that concludes Round 3

I feel like that pretty much wraps up the whole thing, really! Is there any outstanding point that lacks clarity?

[webny99]

And that concludes Round 3

I feel like that pretty much wraps up the whole thing, really! Is there any outstanding point that lacks clarity?

We're definitely getting there  Three things outstanding;

1] All of this I consider to be adequately addressed by modern navigation systems.

GPS is "new" in relative terms, and not used universally. I'm of the belief that roads should be signed such that motorists can reach their destination without GPS technology. So do say more...

2] You declined to comment on a couple of things from my last post; namely, my extension of your bridge analogy (which I may have taken overboard [figuratively, of course] ), and my point that few motorists are going to know the milepost of any given exit off-hand.
As such, I can only assume that you fully concede these points.

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread. I pre-emptively render all references to GPS irrelevant 

And I think that's it from me 

[seicer]

We aren't going for points here, so there is no reason that one has to "concede" any point. There are points to be made for both mile-based and sequential-based exit numbers, although I lean heavily towards the former and not the latter.

Some of these renumbering schemes are almost comical, though. Rhode Island is converting their exits to one based on mileage and because the state is so small, there isn't a huge difference in the sequential and mile numbers. And they are adding exit numbers to previously unnumbered routes, even when they are essentially stubs.

[J N Winkler]

It would show "33" precisely because that is its signed exit number and maps undertake to display the exit numbers that are actually signed in the field.

What? No, no...we're explicitly talking about a case where the exit has no number. Let me see if I can reconstruct the quote sequence fully:

(Omitted for brevity)

So you see, "33" isn't its signed exit number, because it has no exit number, and no exit number is signed in the field. There'd be no reason for a map to display "33". What the exit does have is a milepost; in this case 252. So that's what would display on the map. (The exit may or may not also have a name, which may or may not also be displayed on the map.)

If the exit really has no number, then we are dealing with a situation comparable to that existing in California before 2002, or in the holdout states that still don't number exits on non-Interstate freeways.  The argument for years in California was that exit numbers were not needed because the cross street was enough (counterargument:  there were and still are freeways where a given cross street repeats at different interchanges).  Here in Kansas, I find that lack of exit numbering on non-Interstates leads to unhandy circumlocutions when trying to give directions to a specific exit in a way that allows a stranger driver to gauge his or her progress toward it.

Are you arguing that the status quo should be maintained because most of the benefit of mileage-based exit numbering can be secured by simply publicizing the milepost of each exit on paper maps and in mapping services without changing existing posted sequential exit numbers or posting exit numbers on roads that don't already have them?  If you are, then I would have to disagree, because relatability between mileposts on a map and mileposts in the field is a poor second best to relatability between a mileage-based exit number on a map and the same exit number on tabs secured to the signs actually pertaining to that exit.  Unlike the case with mileposts, which appear just once in a given mile, an exit tab on each large panel sign helps cue a driver looking to take that particular exit.  (The lack of this cueing function caused problems in California back when Caltrans was still operating under a policy that considered an exit number to be signed if it appeared on just one sign in the exit signing sequence, including the gore sign.)  Also, there may be multiple exits in the same mile, mileposts may be absent or obscured by large trucks or bad weather, etc.

Of course. And if the exit doesn't have a number, but you know its milepost, the same applies. But that's not in dispute, is it? People keep mentioning this advantage of mile-based numbering, but I'm not sure why–we all agree that it has this advantage.

With all the palaver about interchange names and identifying exits by milepost without actually signing them using exit numbers based on those mileposts, it was unclear to me that there was agreement on this point.  Moving on!

Extensive, and in every state save one. So–again–I'm not unaware of the advantage of mile-based numbering, and I'm far from unaccustomed to using it. But why should it follow that it needs to be adopted in my state, or any other? Why must anyone who has experienced mile-based numbering insist on it everywhere?

The advantages to navigation (independent of third-party aids such as GPS devices, which BTW are not fully accessible to deaf drivers behind the wheel) pay out in a steady stream over time, while the cost of converting from an existing system is usually a one-time expenditure.  This is why it is usually a technocratic decision to change from sequential to mile-based exit numbering systems and also to eliminate dual-posting ("Mile"/"Exit") systems.  So to object to the change, or to argue for its indefinite postponement in a particular jurisdiction, is effectively to apply a high time preference rate of discount.  If we continue the debate any further, it is more likely to be profitable if we agree in advance on a discount rate, and on ways to value the benefit to motorists, roadside businesses, etc. that accrue from the change.

On the basis of my own experience with exit numbering policy not just in the US but overseas, I will observe that New York has weaker excuses than most for not changing over on the Thruway and Northway.  They are based essentially on failure of route designations to line up with administrative control in such a way that both mileage-based exit numbering and the milepointing on which it is based can be 100% in compliance with the current MUTCD.  But the Thruway already has milepointing which could be used for mileage-based exit numbering if a solution not 100% compliant was deemed acceptable, in much the same way milepointing on the Kansas Turnpike overrides what would otherwise be provided on I-335 (should start at 0, starts at 127), I-470 (jumps from 6 to 177), and I-70 (jumps down from 366 to 182, then jumps back from 224 up to 410).

A country like Britain that sticks to sequential numbering has more of an excuse since there is no underlying milepointing that is fit for the purpose of distance-based exit numbering.  Carriageways are kilometerpointed separately while distance to an upcoming exit is given in miles, location reference signs are poorly designed for legibility and are more likely to be obscured by large trucks, etc.

[Buffaboy]

I can't even keep up with the debate anymore. Someone needs to make a Cliff notes of this because it will take an hour to read the last couple of pages...

[MNHighwayMan]

I can't even keep up with the debate anymore. Someone needs to make a Cliff notes of this because it will take an hour to read the last couple of pages...

Let me summarize it for you:

Mile-based exit numbering is the most logical system.

I may have gotten a slight bias, but I think it's a pretty good boil down.

[webny99]

We aren't going for points here, so there is no reason that one has to "concede" any point.

I'm referring to a "point" in this case as an argument, not a unit of scoring. Obviously, empirestate has no obligation to concede my aforementioned points.

I can't even keep up with the debate anymore. Someone needs to make a Cliff notes of this because it will take an hour to read the last couple of pages...

MNHighwayMan said it pretty well
Empirestate is of the belief that it is not worth the cost for NYS convert to mileage-based exit numbers. JNWinkler and myself have been (individually, so far) attempting to understand and sufficiently dispel his concerns.
Many other details and smaller side-arguments have come into it, and my role in the whole thing is nearing conclusion, but I think that's the jist of it 

[empirestate]

We're definitely getting there  Three things outstanding;

1] All of this I consider to be adequately addressed by modern navigation systems.

GPS is "new" in relative terms, and not used universally. I'm of the belief that roads should be signed such that motorists can reach their destination without GPS technology. So do say more...

I'm of the belief that the technology is widespread enough that it considerably offsets the benefit of mile-based numbering, because it offers the same capability. Even before GPS systems, mapmakers have always included mileages on their maps, and even at that time I'm not sure I would find a conversion warranted. Now that we do have GPS systems, their relative benefit is that much reduced and so I'm that much more sure of my conviction.

2] You declined to comment on a couple of things from my last post; namely, my extension of your bridge analogy (which I may have taken overboard [figuratively, of course] ), and my point that few motorists are going to know the milepost of any given exit off-hand.
As such, I can only assume that you fully concede these points.

An incorrect assumption, as you've no doubt predicted.

The bridge analogy I didn't address because I took it to stem from your misunderstanding that I was referring to the entire subject of exit numbering systems, rather than the sub-discussion about the Thruway. Your other point, about motorists not knowing the mileage of exits offhand, I skipped because I have nothing to add. It's true, of course, and that fact is addressed by various things like maps, GPS systems, and mile-based signage. As I've said pretty thoroughly, I don't find this persuasive to warrant a conversion.

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

And I think that's it from me 

OK, [phew]! Just one more to go.

I can't even keep up with the debate anymore. Someone needs to make a Cliff notes of this because it will take an hour to read the last couple of pages...

I can easily sum up my side of it:
1. Mileage-based numbering has certain advantages related to ease of navigation, calculating distances, etc. These advantages are not of sufficient value to warrant a wholesale conversion of an existing sequential numbering system, such as in New York. Various attempts to persuade me otherwise (by no means limited to this thread, I might add) have so far been unsuccessful.

2. Naming interchanges, rather than numbering them, would be a possible way to uniquely identify them in cases where a numbering system might lead to duplication. However, the need for such a solution appears to be limited enough, and the implementation of it to carry enough disadvantages (of information clutter, primarily), that it doesn't appear worthy of much serious consideration.

[webny99]

I'm of the belief that the technology is widespread enough that it considerably offsets the benefit of mile-based numbering, because it offers the same capability. Even before GPS systems, mapmakers have always included mileages on their maps, and even at that time I'm not sure I would find a conversion warranted. Now that we do have GPS systems, their relative benefit is that much reduced and so I'm that much more sure of my conviction.

1] But in the case of someone without GPS, someone unable to use it, or a GPS failure, doesn't it still make sense for a certain degree of redundance/reinforcement on signage?
2] GPS does not offset the benefits, it simply makes them less noticed (though not less valuable) on average. When those benefits are needed, such as in any off the scenarios above, these benefits are still extremely valuable.

As such, I can only assume that you fully concede these points.

An incorrect assumption, as you've no doubt predicted.

Indeed 

The bridge analogy I didn't address because I took it to stem from your misunderstanding that I was referring to the entire subject of exit numbering systems, rather than the sub-discussion about the Thruway.

My point was that mileage-based numbering can work just fine for the thruway - I wasn't beating around the bush like you made it seem in your analogy - I was touting mileage-based as an acceptable solution for the thruway specifically.

Your other point, about motorists not knowing the mileage of exits offhand, I skipped because I have nothing to add. It's true, of course, and that fact is addressed by various things like maps, GPS systems, and mile-based signage. As I've said pretty thoroughly, I don't find this persuasive to warrant a conversion.

My final question is this; do you think a conversion is inevitable? If so, why postpone it, thereby (unnecessarily) hindering the benefits from being unleashed?

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

[kalvado]

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

Should I remember a list of exits once they are mile-based?

[empirestate]

EDIT:

The pages of long discussion of exit numbering have been moved to https://www.aaroads.com/forum/index.php?topic=22198.0.

Good idea; my response below belongs there, then. My browser had not yet refreshed to show the split while I was composing it.

If the exit really has no number, then we are dealing with a situation comparable to that existing in California before 2002, or in the holdout states that still don't number exits on non-Interstate freeways.  The argument for years in California was that exit numbers were not needed because the cross street was enough (counterargument:  there were and still are freeways where a given cross street repeats at different interchanges).

The difference with California was that the interchanges didn't have numbers, AND the mileposts weren't advertised. In our Verona example, the exit isn't numbered (it's named instead, possibly), but the milepost IS advertised.

Are you arguing that the status quo should be maintained because most of the benefit of mileage-based exit numbering can be secured by simply publicizing the milepost of each exit on paper maps and in mapping services without changing existing posted sequential exit numbers or posting exit numbers on roads that don't already have them?

In the Verona example? No, I'm arguing that identifying the interchange by name, rather than by number, is a more precise way to refer to it uniquely than either identifying it by sequential number (the status quo), or identifying it by its milepost–because either of the latter might be duplicated between different facilities, or even (in the case of the Thruway) within the same facility.

Speaking in general (outside of the Verona example), I'm arguing something similar to that, but not exactly. I'm arguing that part of the benefit of mile-based numbering (probably most, but at least part) is already secured by existing methods of showing point-to-point and/or cumulative distances on maps, as well as (and to a much greater extent) by using modern navigation systems. Whatever remaining benefit is not adequately secured by these methods is not significant enough to warrant any conversion on its own merit.

Of course. And if the exit doesn't have a number, but you know its milepost, the same applies. But that's not in dispute, is it? People keep mentioning this advantage of mile-based numbering, but I'm not sure why–we all agree that it has this advantage.

With all the palaver about interchange names and identifying exits by milepost without actually signing them using exit numbers based on those mileposts, it was unclear to me that there was agreement on this point.  Moving on!

Ah–yes, sorry. As I mentioned, I realize I wasn't entirely clear in keeping those two threads separate.

The advantages to navigation (independent of third-party aids such as GPS devices, which BTW are not fully accessible to deaf drivers behind the wheel) pay out in a steady stream over time, while the cost of converting from an existing system is usually a one-time expenditure.  This is why it is usually a technocratic decision to change from sequential to mile-based exit numbering systems and also to eliminate dual-posting ("Mile"/"Exit") systems.  So to object to the change, or to argue for its indefinite postponement in a particular jurisdiction, is effectively to apply a high time preference rate of discount.  If we continue the debate any further, it is more likely to be profitable if we agree in advance on a discount rate, and on ways to value the benefit to motorists, roadside businesses, etc. that accrue from the change.

And there's the rub–there's no easy way to determine the value, and probably just as many ways of calculating it to support a conversion as to oppose one. I'm not sure whether or how much research has gone into this, but presumably if a firm answer had been found, somebody would have cited it by now. So we just come back to the fact that, since I don't perceive a problem, I don't see the need even to study possible solutions.

On the basis of my own experience with exit numbering policy not just in the US but overseas, I will observe that New York has weaker excuses than most for not changing over on the Thruway and Northway.  They are based essentially on failure of route designations to line up with administrative control in such a way that both mileage-based exit numbering and the milepointing on which it is based can be 100% in compliance with the current MUTCD.  But the Thruway already has milepointing which could be used for mileage-based exit numbering if a solution not 100% compliant was deemed acceptable, in much the same way milepointing on the Kansas Turnpike overrides what would otherwise be provided on I-335 (should start at 0, starts at 127), I-470 (jumps from 6 to 177), and I-70 (jumps down from 366 to 182, then jumps back from 224 up to 410).

I agree that solving the Thruway problem will be much easier than the common wisdom seems to suggest. But what's pertinent to my viewpoint isn't that the excuses for not changing are weak, it's that the excuses for changing are weak. To put it even more fundamentally than that, the whole issue just plain ain't that important.

[empirestate]

1] But in the case of someone without GPS, someone unable to use it, or a GPS failure, doesn't it still make sense for a certain degree of redundance/reinforcement on signage?

Sure, just not a large enough amount of sense to justify a deliberate conversion.

2] GPS does not offset the benefits, it simply makes them less noticed (though not less valuable) on average.

Perhaps "obviate" is a better word than "offset".

The bridge analogy I didn't address because I took it to stem from your misunderstanding that I was referring to the entire subject of exit numbering systems, rather than the sub-discussion about the Thruway.

My point was that mileage-based numbering can work just fine for the thruway - I wasn't beating around the bush like you made it seem in your analogy - I was touting mileage-based as an acceptable solution for the thruway specifically.

OK. Then, in the bridge analogy, I think your viewpoint would be, "You don't need to get across the river."

My final question is this; do you think a conversion is inevitable? If so, why postpone it, thereby (unnecessarily) hindering the benefits from being unleashed?

I'm not sure. Certainly, the current federal administration is advocating for the reduction of oversight and regulation, while also championing large-scale infrastructure investments. So, on the one hand, if the federal government gets out of the business of caring whether NY's exits are numbered correctly, the state will feel no need to change. On the other hand, if such a large infrastructure improvement happens in New York that it requires the replacement of all highway signs anyway, then the question of whether to convert solely for its own sake goes away. So, no, I guess I can't immediately foresee that a conversion is inevitable.

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

Good heavens, I should hope that's clear by now! I really don't think anybody's interested in reading any more of these huge posts where somebody informs me what the advantage is, and I remind them yet again that I already know what it is and that I don't find it persuasive.

[webny99]

OK. Then, in the bridge analogy, I think your viewpoint would be, "You don't need to get across the river."

My take is that saying "you don't need to get across the river" is saying you don't need exit numbers at all. But that's no longer relevant, and pretty much moot at this point.

My final question is this; do you think a conversion is inevitable? If so, why postpone it, thereby (unnecessarily) hindering the benefits from being unleashed?

I'm not sure. Certainly, the current federal administration is advocating for the reduction of oversight and regulation, while also championing large-scale infrastructure investments. So, on the one hand, if the federal government gets out of the business of caring whether NY's exits are numbered correctly, the state will feel no need to change. On the other hand, if such a large infrastructure improvement happens in New York that it requires the replacement of all highway signs anyway, then the question of whether to convert solely for its own sake goes away. So, no, I guess I can't immediately foresee that a conversion is inevitable.

OK, so that's, more or less, the end of the road for me trying to persuade you a renumbering for it's own sake would be worth it. Had you been affirmative, I could have gone down the route I alluded to above 
I should add that the state not feeling the need to change would be a less-than-ideal, in fact probably the worst situation.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

Good heavens, I should hope that's clear by now! I really don't think anybody's interested in reading any more of these huge posts where somebody informs me what the advantage is, and I remind them yet again that I already know what it is and that I don't find it persuasive.

Firstly, I should note my statement cannot also be applied to maps or the likes; the immediacy and accuracy is unique to mileage-based numbers.
Secondly, I can't honestly say I understand exactly why you think a conversion is unjustified; unless you're considering solely your own case and not that of the motoring population at large. It's a one-time expense; not worth postponing. If it is to be done at all, the sooner the better. Permit me to ask outright; do you agree with that final statement?

[webny99]

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

Should I remember a list of exits once they are mile-based?

Sure, if you like. Theres no real need to do so, but some of us roadgeeks, myself included, are apt to do so anyways 

[kalvado]

3] I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

I'd be interested in your response to this comment from 1 upthread.

Sure thing: No, you should not.

Right; so as long as you realize that numbering by mile immediately eliminates the potential for you having to do so, then we're all clear 

Should I remember a list of exits once they are mile-based?

Sure, if you like. Theres no real need to do so, but some of us roadgeeks, myself included, are apt to do so anyways 

Thing is, not remembering exit numbers negates most advantages of mile-based system. Instead of spacing between exits etc - it is distance to target one (if driver remembers that number, as opposed to "exit to Main st. in Sometown)

Anyone having more exposure to mileage-based system than me: can you, from the top of your head, list at least 10-15 numbers along your most traveled route?

[J N Winkler]

Anyone having more exposure to mileage-based system than me: can you, from the top of your head, list at least 10-15 numbers along your most traveled route?

Without cheating:

Kansas I-35

4--US 166 South Haven

19--US 160 Wellington

33--K-53 Mulvane

39--Haysville-Derby

42--I-135/I-235 South Wichita

45--US 54-400 Kellogg Ave.

92--K-177 Cassoday

127--Emporia (I-35 TOTSO)

147--US 56 Admire

177--US 75 South Topeka

182--East Topeka (I-70 TOTSO)

Kansas I-235

7A, 7B--US 54-400 Kellogg Ave.

10--Zoo Blvd.

Kansas I-70

250--I-135 Salina/Wichita

303--K-18 Manhattan

313--K-177 Council Grove/Manhattan

Oklahoma I-35

233--US 177 Braman

194--US 412 Enid/Tulsa

I can go on, but these 18 are among the specific numbers I have most firmly committed to memory because of past use for journey progress tracking.  I also have top mileposts memorized for certain frequently used Interstates (235 for I-35 in both Kansas and Oklahoma, 420-odd for Kansas I-70), as well as milepost ranges for certain metropolitan areas (220's for Shawnee Mission along Kansas I-35, 360's for Topeka along Kansas I-70, 130's for Oklahoma City along Oklahoma I-35).

I can't do any of this reckoning with a sequential system.  NYS, for example, will tell me a group of following exits is for a given city or region (e.g. "Adirondacks Exits 45 - 44 - 43 - 42 - 41," "Albany Exits 24 - 23"), but I don't see this signing until I have arrived, and even if I memorize those numbers for a later repeat visit, without also memorizing the corresponding exit mileposts I have no way of using mileposts to track my progress while I am still quite far out.

When I visited New York last summer, I used the mainline Thruway several times:  Amsterdam-Albany, Amsterdam-Utica, Rome (really Verona)-Rochester.  I had both Google Maps on my phone and a paper map (the NYS official state tourism map, as it happened).  I was able to estimate my total time/distance commitment for each leg in advance using both resources, but since there were no mileage-based exit numbers I could memorize and I didn't have the Thruway's cross-reference log downloaded to my phone, I could not track progress using the mileposts.  On the Amsterdam-Utica leg I was thinking "Is Utica just over the next hill?" for about 20 miles.

[Brandon]

Didn't the Illinois Tollway System (or some other state in the upper Midwest) actually operate that way years ago? Named interchanges with no exit numbers?

ISTHA used no exit numbers what-so-ever until 2010  Driving them was more like driving in California (which also did not have exit numbers till more recently).  However, unlike California and pre-1980 Kansas, ISTHA used (and uses) MUTCD-compliant mileposts, including half-mile mileposts (now every quarter mile).

[Brandon]

Ah–so there's the problem. It does indeed matter how unique it is, because we're dealing with the specific situation where you might have an "exit 106" on one part of the Thruway, and another "exit 106" on another part of it. So we see that mile-based numbering isn't completely unique. However, if the first exit were instead called "Circleville Interchange" and the other were called "Squaretown Interchange", then the identification is unique.

False problem.  The Tri-State Tollway has two of the following exit numbers:
2 - Halsted Street (IL-1), and Rosecrans Road (IL-173).
8 - 147th Street, and Grand Avenue (IL-132).
27 - Waukegan Road (IL-43), and Ogden Avenue (US-34).

Yet, no one gets them mixed up.  Why?  Because one set belongs to I-94, and one set belongs to I-294.
If implemented on the New York Thruway, one set of exit numbers would be for I-90, and one set would be of I-87.  They could never get mixed up for the same reason the Tri-State Tollway exit numbers do not get mixed up.

[Brandon]

I don't know how far it is between Exit 4 and Exit 11A on the Mass Pike. Should I have to remember a milepost for every single exit number?

No, that's ridiculous.  That's also where distance-based exit show their superiority.  I drove in the northeast last year, and it was a right royal pain in the ass to figure out where the next exit was due to their moronic sequential exit numbering systems.