Largest Numerical Difference in a Numbered Junction

[Avalanchez71]

My bet is US 1 to SR 9336 in Florida City, FL.  Anyone know of such a large difference from the sum of 9336 - 1?

[Max Rockatansky]

Appears to be I-980 and CA 24 for California. 

[oscar]

10243: US 29 with secondary 10272 (signed with white rectangles), at Lee Hwy/Nutley St. n Fairfax VA.

[NWI_Irish96]

Indiana doesn't have 4-digit highways so it won't get close to the largest nationally, but the largest in the state is IN 931 at IN 4 in Lakeville.

[Avalanchez71]

10243: US 29 with secondary 10272 (signed with white rectangles), at Lee Hwy/Nutley St. n Fairfax VA.

That takes the cake if you factor in those little white rectangles for sure.

[kphoger]

But what about "fractional" highways in WV or hyphenated highways in LA?

[1995hoo]

10243: US 29 with secondary 10272 (signed with white rectangles), at Lee Hwy/Nutley St. n Fairfax VA.

10,332: US-1 with secondary 10333, Birch Crest Way, in Lorton.

https://goo.gl/maps/qezGjy7pdEZJniug6

[Mapmikey]

10243: US 29 with secondary 10272 (signed with white rectangles), at Lee Hwy/Nutley St. n Fairfax VA.

That takes the cake if you factor in those little white rectangles for sure.

The winner in Fairfax County is 10562:  US 50 with SR 10612 - https://goo.gl/maps/xW58JGb5Fm4ZkcHr9

[kphoger]

But what about "fractional" highways in WV or hyphenated highways in LA?

For example, here is the intersection of US 522 @ WV (secondary) 522|12.
Does that count as 52212—522=51690?

[1995hoo]

But what about "fractional" highways in WV or hyphenated highways in LA?

For example, here is the intersection of US 522 @ WV (secondary) 522|12.
Does that count as 52212—522=51690?

I realized we could beat that one provided that "secret" route numbers count. The eastbound Dulles Access Road has a direct exit to Route 7. The Dulles Access Road's unposted route number is 90004, giving a difference of 90004 — 7 = 89,997.

[TEG24601]

HI 76 and HI 7101 near Waipahu, HI

[Mapmikey]

But what about "fractional" highways in WV or hyphenated highways in LA?

For example, here is the intersection of US 522 @ WV (secondary) 522|12.
Does that count as 52212—522=51690?

I realized we could beat that one provided that "secret" route numbers count. The eastbound Dulles Access Road has a direct exit to Route 7. The Dulles Access Road's unposted route number is 90004, giving a difference of 90004 — 7 = 89,997.

Secret 90005 has a direct interchange with US 1...

[1995hoo]

But what about "fractional" highways in WV or hyphenated highways in LA?

For example, here is the intersection of US 522 @ WV (secondary) 522|12.
Does that count as 52212—522=51690?

I realized we could beat that one provided that "secret" route numbers count. The eastbound Dulles Access Road has a direct exit to Route 7. The Dulles Access Road's unposted route number is 90004, giving a difference of 90004 — 7 = 89,997.

Secret 90005 has a direct interchange with US 1...

Good point. I forgot US-1 runs concurrently with I-395 there. You'd think I'd remember that because I've driven over the bridge so many times, but I probably don't even notice most of the signs most of the time because the road is so familiar.

[US 89]

The largest one for Utah is probably 309 - at the junction of SR 9 and SR 318 west of Hurricane.

[GaryV]

Michigan is clearly I-696 at M-1.  The highest number in the state and the lowest number.

[Max Rockatansky]

For Arizona it would be I-10 and AZ 587. 

[oscar]

I realized we could beat that one provided that "secret" route numbers count. The eastbound Dulles Access Road has a direct exit to Route 7. The Dulles Access Road's unposted route number is 90004, giving a difference of 90004 — 7 = 89,997.

That "route number" and similar 90xxx numbers are assigned by VDOT for roads it doesn't control, but are owned and maintained by Federal agencies, for traffic and other statistics. I wouldn't consider them "route numbers" at all. This is unlike the other 5-digit routes in Virginia mentioned upthread, for VDOT-maintained secondary roads, which usually have some route number signage.

They are more like Alaska's unsigned 6-digit internal inventory numbers, which I also would not count. However, all the really low (western Alaska) and the really high (southeastern Alaska) inventory numbers are for roads isolated from the main highway network, and which have no intersections with the main network. The largest difference I could find within the main network is 150990 (Wiseman Road, off the Dalton Highway/AK 11 near Coldfoot) and 273010 (Wiseman/Nolan Road, branch from Wiseman Road), for a diff of 122020.

HI 76 and HI 7101 near Waipahu, HI

For Hawaii, you can do better: H-1 and HI 8930, near Kapolei.

HI 76 and HI 7101 also intersect HI 7110.

[hbelkins]

Given that Kentucky has regular state routes signed well into the 3000s, and with some 6000-series frontage routes in western Kentucky signed, I'm not sure I would attempt to find our example.

Here's KY 69 intersecting KY 6122.

2018 South- and West-Central KY Day 2 - 051 by H.B. Elkins, on Flickr

[Avalanchez71]

But what about "fractional" highways in WV or hyphenated highways in LA?

Depends if you are trying to divide with the fraction or not.

[Max Rockatansky]

With Nevada I believe the largest is NV 88 and NV 756. 

[TheHighwayMan3561]

Minnesota's is US 10 and I-694. 694 used to have an interchange with MN 5, but the latter route was truncated back past that interchange.

[FrCorySticha]

I think Montana's is Secondary 573 at MT 16 in Medicine Lake (NE corner of the state)

[JayhawkCO]

For Colorado, it looks like 462.  CO8 & CO470 in/near Morrison.

Chris

[TheGrassGuy]

NJ is 439 and 1

[KCRoadFan]

And what about Texas, what with all its four-digit FM roads?