Classes of "Clinching"

[Rothman]

Hypothetical: a state highway has a brief concurrency with an Interstate highway. I've driven the concurrent section and the sections of the state highway on either side of the concurrency individually at three different times. Does it count as a composite clinch even though I used none of the on/offramps that would be required to drive the whole state highway in one go?

Is what I wrote even intelligible?   

1) No

Why not? Although I can't say I've run into this situation personally. I'm not sure the ramps I'm assuming you insist must be driven are technically part of the route, but it depends on the situation. A diamond interchange in the country where a route leaves an interstate is different from a major city interchange.

If I'm understanding correctly, the state route follows the interstate ramps, so the ramps are technically part of the continuous route.

Sometimes it doesn't though. I remember there was a thread discussing TOTSOs, and in Tennessee, I seem to recall, the official state route follows the centerline of one freeway and then turns immediately at the centerline of another freeway, and that none of the ramps you would actually take to get from one of the freeways to the other (and thus stay on the same route number) is technically part of the route itself.

That is the official route follows the blue line in the picture below and not any of the red lines:

I find that hard to believe and more because TN's got a lazy GPS coder.

Isn't the I-76/I-80 interchange in Ohio the same way?

I-76/I-80 has the toll ramp complication.  This TN sillyness is different.

[royo6022]

Hypothetical: a state highway has a brief concurrency with an Interstate highway. I've driven the concurrent section and the sections of the state highway on either side of the concurrency individually at three different times. Does it count as a composite clinch even though I used none of the on/offramps that would be required to drive the whole state highway in one go?

Is what I wrote even intelligible?   

1) No

Why not? Although I can't say I've run into this situation personally. I'm not sure the ramps I'm assuming you insist must be driven are technically part of the route, but it depends on the situation. A diamond interchange in the country where a route leaves an interstate is different from a major city interchange.

If I'm understanding correctly, the state route follows the interstate ramps, so the ramps are technically part of the continuous route.

Sometimes it doesn't though. I remember there was a thread discussing TOTSOs, and in Tennessee, I seem to recall, the official state route follows the centerline of one freeway and then turns immediately at the centerline of another freeway, and that none of the ramps you would actually take to get from one of the freeways to the other (and thus stay on the same route number) is technically part of the route itself.

That is the official route follows the blue line in the picture below and not any of the red lines:

I find that hard to believe and more because TN's got a lazy GPS coder.

What about rest area ramps for interstates? Do the ramps count as part of the route? It would seem rather redundant for them to count because then you're guaranteed to skip over the main section of the route between the entrance and exit ramps of the rest areas... so why wouldn't that also apply to ramps from the route you're clinching to other highways?

[Rothman]

Hypothetical: a state highway has a brief concurrency with an Interstate highway. I've driven the concurrent section and the sections of the state highway on either side of the concurrency individually at three different times. Does it count as a composite clinch even though I used none of the on/offramps that would be required to drive the whole state highway in one go?

Is what I wrote even intelligible?   

1) No

Why not? Although I can't say I've run into this situation personally. I'm not sure the ramps I'm assuming you insist must be driven are technically part of the route, but it depends on the situation. A diamond interchange in the country where a route leaves an interstate is different from a major city interchange.

If I'm understanding correctly, the state route follows the interstate ramps, so the ramps are technically part of the continuous route.

Sometimes it doesn't though. I remember there was a thread discussing TOTSOs, and in Tennessee, I seem to recall, the official state route follows the centerline of one freeway and then turns immediately at the centerline of another freeway, and that none of the ramps you would actually take to get from one of the freeways to the other (and thus stay on the same route number) is technically part of the route itself.

That is the official route follows the blue line in the picture below and not any of the red lines:

I find that hard to believe and more because TN's got a lazy GPS coder.

What about rest area ramps for interstates? Do the ramps count as part of the route? It would seem rather redundant for them to count because then you're guaranteed to skip over the main section of the route between the entrance and exit ramps of the rest areas... so why wouldn't that also apply to ramps from the route you're clinching to other highways?

No.

[Scott5114]

Hypothetical: a state highway has a brief concurrency with an Interstate highway. I've driven the concurrent section and the sections of the state highway on either side of the concurrency individually at three different times. Does it count as a composite clinch even though I used none of the on/offramps that would be required to drive the whole state highway in one go?

Is what I wrote even intelligible?   

1) No

Why not? Although I can't say I've run into this situation personally. I'm not sure the ramps I'm assuming you insist must be driven are technically part of the route, but it depends on the situation. A diamond interchange in the country where a route leaves an interstate is different from a major city interchange.

If I'm understanding correctly, the state route follows the interstate ramps, so the ramps are technically part of the continuous route.

Sometimes it doesn't though. I remember there was a thread discussing TOTSOs, and in Tennessee, I seem to recall, the official state route follows the centerline of one freeway and then turns immediately at the centerline of another freeway, and that none of the ramps you would actually take to get from one of the freeways to the other (and thus stay on the same route number) is technically part of the route itself.

That is the official route follows the blue line in the picture below and not any of the red lines:

Hell, Colorado's got some US route that does that at an overpass where there aren't even any ramps.

[vdeane]

NY is an interesting case.  Looking at the mile markers for I-87, Northway mile 0 is at the overpass over I-90, not on any of the ramps.  That said, the GIS files do indeed have I-87 on the ramps.  Also, this used to be a cloverleaf, so the mile marker would have been accurate for I-87 taking the ramps back then (northbound would use a loop).