Loops of endings

[pianocello]

is there one involving only interstate highways?  I cannot think of one offhand. 

Probably not, since (almost?) every interstate endpoint will eventually get you to I-5, I-95, a US or state highway, an infinite loop (69 ending at 465), or an international border.

[Takumi]

The only interstate one I can think of is a two: I-64 ends at I-664, I-664 ends at I-64.

[NE2]

The only Interstates I came up with are beltways (64-664, 255-270, 494-694, etc.). As well as 95-295 for now.
BUT there will be 76-295-195-276 in the future.

[Big John]

The only interstate one I can think of is a two: I-64 ends at I-664, I-664 ends at I-64.

Once the US 41 interstate conversion is complete, it is likely that the new interstate (probably I-41) and I-43 will end each other by Green Bay.

[Alps]

is there one involving only interstate highways?  I cannot think of one offhand. 

Probably not, since (almost?) every interstate endpoint will eventually get you to I-5, I-95, a US or state highway, an infinite loop (69 ending at 465), or an international border.

I-10 and I-90 are other "problems" that end the fun prematurely.

I-12 I-59 I-24 I-57 I-55... sooooo close but it goes past I-12 down to 10. That's the best I can do with 2di's.

[mgk920]

US 41 ends a lot of the 'fun' here in Wisconsin, too.



Mike

[Michael]

Three involving NY 89 (technically, they fall apart at NY 89/NY 104, but I figured I'd post them anyway):

1:

• The southern end of NY 89 is at NY 13/34/96 in Ithaca
• NY 13 ends at NY 3 about two miles west of Pulaski
• NY 3 ends at NY 104 in Hannibal
• The northern end of NY 89 is at NY 104 just outside of Wolcott

2 (variation of #1):

• The southern end of NY 89 is at NY 13/34/96 in Ithaca
• NY 13 ends at NY 3 about two miles west of Pulaski
• NY 104B ends at NY 3
• The other end of NY 104B is at NY 104
• Both ends of NY 104A are along NY 104 before the next step (but that might be considered cheating)
• The northern end of NY 89 is at NY 104 just outside of Wolcott

3:

• The southern end of NY 89 is at NY 13/34/96 in Ithaca
• NY 34 ends at NY 104 south of Hannibal*
• The northern end of NY 89 is at NY 104 just outside of Wolcott

      *Before NY 34 was extended to NY 104, this step would be NY 370 to NY 104