NY: I-495 Exit Numbers

[Markkos1992]

1.   Should the 69th St/Grand Ave interchange have its own number (19A)?
2.   23B should be 22B or 22C.
3.   Are we missing a graph connection at the Northern State Pkwy connection between 45 and 46?  (unnumbered interchange makes me want to go no-build if possible)
4.   Do you consider the eastbound on-ramp east of Pinelawn Rd as part of Exit 49?
5.   Should 54 be 53A?

[yakra]

1.   Should the 69th St/Grand Ave interchange have its own number (19A)?

I'm fine with leaving it out. There's no access to/from the west. Westbound drivers will exit the mainline at 19 anyway, so I don't see need to add a new point.
Even though I'm more inclined to think of C/D roads as part of the route than frontage roads.
I'm receptive to being outvoted here. Eastbound, there is an entrance just E of 80th St, so there's that. Hmm...

2.   23B should be 22B or 22C.

Going with 22C, the less ambiguous of the two.

3.   Are we missing a graph connection at the Northern State Pkwy connection between 45 and 46?  (unnumbered interchange makes me want to go no-build if possible)

Yeah, unnumbered interchanges on otherwise exit-numbered routes are ugly, though I've sometimes done them.
The entrance ramps do kind of fill in the missing movements from the Exit 45 interchange, in typical NYC metro area geometry-and-ROW-constraints Breezewoody fashion. I'm sort of inclined to think of it as part of the Exit 45 complex in that respect.
One possibility is to move exit 45 to the Parkway, though that'd be a bit awkward relative to what's signed Exit 45, as it's positioned now.
No-build is another possibility. We can still follow indirectly with one more connection via NY135. Not the least convenient thing in the world.

4.   Do you consider the eastbound on-ramp east of Pinelawn Rd as part of Exit 49?

Ick. There is that other EB onramp right there at NY110 itself, sort of implying this is something different. Not quite comfortable calling it 49A, as it's not signed as part of Exit 49 (or, well, anything).
Heck, call it part of Exit 49. It complements the WB Exit 49N ramp, putting it right there in the same footprint. 1PPI. One interchange, multiple ramps. I've occasionally done similar things in Texas.

5.   Should 54 be 53A?

Changed locally.

[Markkos1992]

3.   Are we missing a graph connection at the Northern State Pkwy connection between 45 and 46?  (unnumbered interchange makes me want to go no-build if possible)

Yeah, unnumbered interchanges on otherwise exit-numbered routes are ugly, though I've sometimes done them.
The entrance ramps do kind of fill in the missing movements from the Exit 45 interchange, in typical NYC metro area geometry-and-ROW-constraints Breezewoody fashion. I'm sort of inclined to think of it as part of the Exit 45 complex in that respect.
One possibility is to move exit 45 to the Parkway, though that'd be a bit awkward relative to what's signed Exit 45, as it's positioned now.
No-build is another possibility. We can still follow indirectly with one more connection via NY135. Not the least convenient thing in the world.

I think you could get me to agree with adding a 46A at the Parkway.

I wonder how many travelers are currently using the 37A label on the Northern State Parkway.

[yakra]

I wonder how many travelers are currently using the 37A label on the Northern State Parkway.

3 -- dharwood & snowedin have I-495 solidly marked off thru the area and would only need this point in the unlikely case they exited @ 45 & re-entered via the Parkway, while nezinscot may be able to use a point here.

[Duke87]

Looking at the situation I think I-495 needs a point where it crosses the Northern State. Not just for graph connection but because this is a distinct interchange, albeit one that happens to only have entrance ramps from 495's perspective.

So I would add a point here but given its position it would be called 45A (not 46A).

[Markkos1992]

Looking at the situation I think I-495 needs a point where it crosses the Northern State. Not just for graph connection but because this is a distinct interchange, albeit one that happens to only have entrance ramps from 495's perspective.

So I would add a point here but given its position it would be called 45A (not 46A).

45A is fine.  I guess I got confused by the OSM exit numbers.

[yakra]

The (lack of) graph connection is not a dealbreaker IMO. This is all right next to NY135, so it only takes 2 more mouse clicks to navigate from one route to the other.
It's less clear cut on being a distinct interchange too -- part of a larger flyswatter complex with some movements indirect or Breezewooded out. Compare South Portland.

[Duke87]

It's less clear cut on being a distinct interchange too -- part of a larger flyswatter complex with some movements indirect or Breezewooded out. Compare South Portland.

I mean, South Portland has a point everywhere that two roads meet, though it also doesn't have any points where one road only has entrances and no exit. What exactly is the intended comparison?

At any rate, on the Northern State Parkway, Manetto Hill Road (37) and Sunnyside Blvd (38) both get different points from I-495 (37A). The destinations for 37 and 38 on NorStaPkwy are the same as the destinations for 45 and 46 on I-495, and the points for 37 and 38 are about the same distance from 37A as 45 and 46 on I-495 would be from proposed 45A (37-37A is definitively closer than 45-45A would be, even).
So how does it make any sense to 1PPI out 45A on I-495 but not 37A on NorStaPkwy? The status quo is inconsistent between the two.

[vdeane]

It's also worth noting that there's a similar interchange to the west (really the other half of the one we're talking about, just with other interchanges in between), which does have points on both roads.  It's 42 on I-495 and 35A on the NSP.

[yakra]

What exactly is the intended comparison?

part of a larger flyswatter complex with some movements indirect or Breezewooded out.

At any rate, on the Northern State Parkway, Manetto Hill Road (37) and Sunnyside Blvd (38) both get different points from I-495 (37A). The destinations for 37 and 38 on NorStaPkwy are the same as the destinations for 45 and 46 on I-495, and the points for 37 and 38 are about the same distance from 37A as 45 and 46 on I-495 would be from proposed 45A (37-37A is definitively closer than 45-45A would be, even).
So how does it make any sense to 1PPI out 45A on I-495 but not 37A on NorStaPkwy? The status quo is inconsistent between the two.

Not at all. NorStaPkwy exits 37 & 38 are complete interchanges in their own right. 37A is an additional partial interchange.
On I-495, 46 is a complete interchange. Then, there's a partial interchange at the NSP and another partial interchange at Manetto Hill Rd. The question then becomes deciding between
• partial interchange -> a point + another partial interchange -> another point, vs
• partial interchange + partial interchange = a single (partial) interchange -> one point.
Worth noting that the EB offramp at current 45 complements the ramps at the NSP; no EB offramp is available there.
It's not enough IMO to look at just the directly connected roads or what directions are signed; that's part of a larger picture.

"Double half" terminology aside, this meets neither the "clear gap of at least 0.5 mi/0.8 km separat[ing] the two halves" nor the "each half connects to a different highway that we are also mapping" criteria.
I could be talked into moving the point onto the NSP per "use one central point" grounds. Only nezinscot is using NY I-495 45; this would make his travels nice & continuous on mapview.

It's also worth noting that there's a similar interchange to the west (really the other half of the one we're talking about, just with other interchanges in between), which does have points on both roads.  It's 42 on I-495 and 35A on the NSP.

Similar in that there are 2 ramps to go from Hwy A to Hwy B proceeding in the same direction.
Dissimilar in that there's not a complementary adjacent partial interchange to cause debate about whether to collapse to a single point.

[Duke87]

"Double half" terminology aside, this meets neither the "clear gap of at least 0.5 mi/0.8 km separat[ing] the two halves" nor the "each half connects to a different highway that we are also mapping" criteria.

So, methinks we need to define "double half interchange". When I see that term I think of something like this, where what cleanly functions as a single interchange with all ramps serving the same destination(s) is split in two. I would not interpret the 495/NSP situation as being "double half" at all since the two "halves" serve different destinations.

As for the "it's a Breezewood" argument, it isn't really in this case because exit 45 is not signed as nor does it logically serve as completing a missing connection to the NSP from 495. The missing connection that could be made here is served directly by exit 42, and if you missed that or got on east of there it can be made without exiting to local streets via NY 135 at exit 44.

Nonetheless, a manual revision to better define this term would be worthwhile IMO.

I could be talked into moving the point onto the NSP per "use one central point" grounds. Only nezinscot is using NY I-495 45; this would make his travels nice & continuous on mapview.

Okay, this definitely validates the need for a point where the two highways cross.

So, moving the point for 45 would be better than the status quo, at least, though still a less robust solution than creating a separate point.

[Markkos1992]

Speaking of I-495/Northern State Pkwy connectors, should the 35A point on the Northern State Pkwy be just plain I-495 or I-495(42)?

[rickmastfan67]

Looking at the situation I think I-495 needs a point where it crosses the Northern State. Not just for graph connection but because this is a distinct interchange, albeit one that happens to only have entrance ramps from 495's perspective.

I'm also in the camp that there 100% should be a graph connection between Northern State Parkway & I-495 there.

Especially when you factor in the 'educational' part of the project for Jim, where he needs graph connections for his classes.

This is 100% a legit connection between the two.  So what if I-495 doesn't have ramps 'to' the Norther State Parkway?  Even just 1 ramp directly connecting the two (w/o any intermediate intersection breaking it up) is justification IMO for a graph connection.

Take a look @ I-70 & E470 in CO.  We have a single ramp there from NB E470 to WB I-70, but we have a graph connection.  Why not here too?

Also, look @ '35A' on the 'Northern State Parkway'.  Same situation as I-495 (2 on-ramps, no off-ramps), except there's a point here in the file.  Only difference is there's no legit graph connection here because the highways stay on separate paths.  In fact, you could say that those other ramps @ 37A are the 'sister' ramps for these @ 35A.