US 6 may actually be LONGER than US 20

[NWI_Irish96]

I added up all the individual state mileage for each route listed on the Travel Mapping website and got 3289.73 for US 20 and 3216.93 for US 6.

The real question is, how many people have actually driven the full length of US 6 and US 20? Most I can claim for 6 is the 95 overlap in Nevada and from I-15 to US 191 in Utah.
US 20, however, I have from Newport Oregon to Cody Wyoming.

My longest segments are from Morris, IL to Sandusky, OH on US 6 and from Marengo, IL to OH 49 on US 20.

[Flint1979]

doesn't US 6 have a weird gap in western Colorado?

I believe that it's mostly unsigned in Colorado and concurrent with I-70 for most of the length west of Denver and concurrent with I-76 for most of the length east of Denver and on it's own path east of Sterling. It's about 467 miles in Colorado those switchbacks in the mountains probably add on a ton of miles.

[Flint1979]

I don't think I have spent a ton of time on US-6 but have spent some time on US-20. What is the mileage for US-20 in Wyoming? I haven't made it that far west.

[US 89]

US 6 enters Colorado unsigned at I-70 at Utah and exits at the unsigned Mack spur (I-70 Exit 11). Once it rejoins its original alignment, it's signed east through Fruita, Grand Junction, and Clifton and then back onto I-70 at exit 44.

Don't forget the "END US 6" sign in Mack just past where it turns toward 70.

[usends]

using a method that I believe to be quite accurate (and in some cases, more accurate than the "official" distances posted by state departments of transportation)

And what method would that be?

Google Maps.  I measure the mileage through each state in segments of less than 100 miles in order to get results that have a precision to the tenth-mile.  Of course I often have to go in and "pin" the route so that GMaps doesn't divert me onto a nearby freeway.  Once I've added up all the segments in a given state, I reality check it by comparing my results to the official DOT figure.  Probably 95% of the time my measurements are very closely aligned with the DOT measurements, which is why I am quite confident about the accuracy of this method.  And it also allows me to confidently attribute the 5% of mismatches to DOT errors (after I have gone back to make sure I am measuring all of the correct route segments). 

[usends]

I am suspicious of any methodology that doesn't use official DOT/AASHTO resources. Having dealt with this type of question dozens of times on Wikipedia with state routes, if you start straying from official sources, you risk misidentifying what the "real" route is.

I am suspicious of official DOT/AASHTO resources.  I can appreciate your position, but I have seen plenty of examples where the data is either a.) wrong due to human error, b.) wrong because it's outdated, c.) internally inconsistent, or d.) correct but not intended for measuring border-to-border mileage (as you and I have discussed previously).  Regardless, if DOT data is accurate, it should be able to stand up to a little fact-checking.  And (as I discussed in post #30) 95% of the time my results do match up well with the official DOT figure.

So questions that I feel like need to be answered for this claim to hold up:
1) Where did the US 20 mileage in Yellowstone come from, anyway? Who published it? AASHTO? The Park Service?

NPS official maps (here and here) indicate mileages between NPS boundaries and selected junctions.  Based on those mileages, one of the implied routes of US 20 through Yellowstone (via the South Loop) is 95 miles, and the other implied route (via Norris Canyon) is 83 miles.  But note that all mileages shown there are rounded to the nearest integer, which means each segment is over- or under-stated by up to a half-mile.  Each route through the Park consists of five measured segments, and when we multiply the half-mile times those five segments, the total distance could be off by +/- 2.5 miles.  My own measured distance of 93.8 miles via South Loop falls within that error margin.  My own measured distance of 80.1 miles via Norris Canyon is .4 mile outside of that error margin.

2) What route does this US 20 mileage use? What agency asserts that the road in question is the route of US 20?
3) What agency maintains that road?

I need some clarification before answering these questions.  Are you asking all of these in reference to implied US 20 mileage through Yellowstone?  If so, then what is your position regarding US 20's total mileage?  Should an implied route through Yellowstone be included in the total, or not?  The only reason I measured it was so I would know how much mileage to subtract from the distance required to drive US 20 from coast-to-coast.

[usends]

Don't forget the "END US 6" sign in Mack just past where it turns toward 70.

A perfect illustration of one of the points I'm trying to make: government agencies are capable of making mistakes.  Sometimes a little discernment is necessary in order to evaluate the accuracy of official information.

[ClassicHasClass]

That must be relatively recent because it was not there in 2006: http://www.floodgap.com/roadgap/6/u10/#sec_13

However, with the exception of the Interstate "co-signed not really" portions, my impression is that US 6 in Colorado was hardly unsigned.

[Rothman]

I'd trust DOT data over an amateur roadgeek's fiddling with Google Maps.

[Scott5114]

I am suspicious of any methodology that doesn't use official DOT/AASHTO resources. Having dealt with this type of question dozens of times on Wikipedia with state routes, if you start straying from official sources, you risk misidentifying what the "real" route is.

I am suspicious of official DOT/AASHTO resources.  I can appreciate your position, but I have seen plenty of examples where the data is either a.) wrong due to human error, b.) wrong because it's outdated, c.) internally inconsistent, or d.) correct but not intended for measuring border-to-border mileage (as you and I have discussed previously).  Regardless, if DOT data is accurate, it should be able to stand up to a little fact-checking.  And (as I discussed in post #30) 95% of the time my results do match up well with the official DOT figure.

Right, and your Google Maps method is something I've used before, when state DOT data is useless for the purpose. For example, Oklahoma's official mileage is pieced out by control section, which may or may not correspond to the location of actual junctions, so if you're wanting milepost numbers, Google is your only option. Google data can be kind of wonky, too, though; it's only precise to one decimal place, whereas DOT data often goes out to two or three. Also, when there's a closure along the route, you cannot get Google data from it no matter how hard you try.

So questions that I feel like need to be answered for this claim to hold up:
1) Where did the US 20 mileage in Yellowstone come from, anyway? Who published it? AASHTO? The Park Service?

NPS official maps (here and here) indicate mileages between NPS boundaries and selected junctions.  Based on those mileages, one of the implied routes of US 20 through Yellowstone (via the South Loop) is 95 miles, and the other implied route (via Norris Canyon) is 83 miles.  But note that all mileages shown there are rounded to the nearest integer, which means each segment is over- or under-stated by up to a half-mile.  Each route through the Park consists of five measured segments, and when we multiply the half-mile times those five segments, the total distance could be off by +/- 2.5 miles.  My own measured distance of 93.8 miles via South Loop falls within that error margin.  My own measured distance of 80.1 miles via Norris Canyon is .4 mile outside of that error margin.

2) What route does this US 20 mileage use? What agency asserts that the road in question is the route of US 20?
3) What agency maintains that road?

I need some clarification before answering these questions.  Are you asking all of these in reference to implied US 20 mileage through Yellowstone?  If so, then what is your position regarding US 20's total mileage?  Should an implied route through Yellowstone be included in the total, or not?  The only reason I measured it was so I would know how much mileage to subtract from the distance required to drive US 20 from coast-to-coast.

Mostly, I'm interested in who, if anyone, claims responsibility for US 20 through that stretch. If the same agency has designated an official routing and has mileage for that, that's probably US 20. If NPS maintains the road through there but doesn't have an officially-designated US 20 routing, it's probably a gap in the route.

[Max Rockatansky]

Has anyone ever reached out to the Park Museum at Yellowstone for information on possible official routines of the US Routes?  I've reached out to other Park museums regarding historical highway information and they usually have something. 

[Mapmikey]

Has anyone ever reached out to the Park Museum at Yellowstone for information on possible official routines of the US Routes?  I've reached out to other Park museums regarding historical highway information and they usually have something. 

The US routes do not exist in YNP.

See pdf pg. 21 of the 5th pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 89 defined to end at South Entrance

See pdf pg. 28-29-30 at the 6th (last) pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 14 and US 287 defined to end at Yellowstone Park boundary
US 89 defined to end at Gardiner entrance and south entrance of the park

[Scott5114]

Has anyone ever reached out to the Park Museum at Yellowstone for information on possible official routines of the US Routes?  I've reached out to other Park museums regarding historical highway information and they usually have something. 

The US routes do not exist in YNP.

See pdf pg. 21 of the 5th pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 89 defined to end at South Entrance

See pdf pg. 28-29-30 at the 6th (last) pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 14 and US 287 defined to end at Yellowstone Park boundary
US 89 defined to end at Gardiner entrance and south entrance of the park

This is right–as far as the state highway department is concerned. If NPS maintains the road through the park and has a declared alignment through the park it would still be continuous, regardless of what the state highway department says. But it appears that's not likely to be the case.

[usends]

Adding up referenced DOT mileages for each state, I'm getting roughly 3220 miles (can't find an official mileage for Wyoming). That makes it longer than US 6.

So even if we set aside the idea that the DOT mileages might not be exactly right, we can still see that AASHTO's "official" figure of 3365 miles is way off.  Even if that figure included the mileage through Yellowstone, that still wouldn't account for a difference of 145 miles.

[Mapmikey]

Has anyone ever reached out to the Park Museum at Yellowstone for information on possible official routines of the US Routes?  I've reached out to other Park museums regarding historical highway information and they usually have something. 

The US routes do not exist in YNP.

See pdf pg. 21 of the 5th pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 89 defined to end at South Entrance

See pdf pg. 28-29-30 at the 6th (last) pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 14 and US 287 defined to end at Yellowstone Park boundary
US 89 defined to end at Gardiner entrance and south entrance of the park

This is right–as far as the state highway department is concerned. If NPS maintains the road through the park and has a declared alignment through the park it would still be continuous, regardless of what the state highway department says. But it appears that's not likely to be the case.

In this case AASHO also says US routes are not in Yellowstone.  If it is accepted that US 441 is not in GMSP despite there being only one defined road through the park, then I think we must accept no US routes in Yellowstone if both the state and AASHO say that and there is no posted route through the park for even the obvious corridors.

[kphoger]

Right.

AIUI, there is zero evidence supporting the notion that US-20 exists within Yellowstone.  Or am I missing something?

[Mapmikey]

I finally found my 1989 spreadsheet of US routes.

It does not count Yellowstone for US 20 at all (US 89 is also split; oddly, US 441's mileage through GSMNP is included).  The east segment is 2500 miles and the west segment is 865 miles for a total of 3365.

However, it counts all the US 20 Bus and US 20 ALT routes in these totals!

Subtracting these out gets an east segment of 2376 miles and a west segment of 861 miles for a total of 3237 miles (in 1989...freewayization in Iowa has likely shortened it a little more)

For US 6: 3249 miles for full list which includes all US 6 ALT, US 6 Bus, US 6 Byp and US 6N.

Subtracting out everything gives 3208 miles.  For the curious, it credits Colorado with 474 miles.

The actual difference between US 6 and US 20 on this is close enough that even what I did there won't conclude the question because Iowa may not be the only changes in the last 31 years (and who knows how much of Iowa it has correct as of 1989) for either route.  For instance, two Pennsylvania bypasses of US 6 are not yet on there. 

Posted mile markers in the field aren't necessarily sacrosanct either as states will sometimes not move/change markers after mid-state changes somewhere.

So either up to date state logs or google measurements along the known route may be the best that can be done.

[CNGL-Leudimin]

That gap through Yellowstone made me believe US 6 was (still) the longest US Route until I added the lengths of both segments of US 20.

However I believe the only US Route to exist twice is US 2 (I have indexed the Western one as US 0). All others are continuous, be it via ferry (US 9, US 10 -officially defined as such-, formerly also US 16) or via implied routes (US 422 over US 22 and US 322 -originally just US 22-, all the Yellowstone routes including US 20). Therefore, I consider US 20 to be around 3300 miles (5300 km) long, including the implied section thru Yellowstone and thus about 100 miles (160 km) longer than US 6.

[Max Rockatansky]

Has anyone ever reached out to the Park Museum at Yellowstone for information on possible official routines of the US Routes?  I've reached out to other Park museums regarding historical highway information and they usually have something. 

The US routes do not exist in YNP.

See pdf pg. 21 of the 5th pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 89 defined to end at South Entrance

See pdf pg. 28-29-30 at the 6th (last) pdf here - https://drive.google.com/drive/folders/1kmrrq5P2bx3RQgkhu-JXDBWABUV85b_X
US 14 and US 287 defined to end at Yellowstone Park boundary
US 89 defined to end at Gardiner entrance and south entrance of the park

This is right–as far as the state highway department is concerned. If NPS maintains the road through the park and has a declared alignment through the park it would still be continuous, regardless of what the state highway department says. But it appears that's not likely to be the case.

And there are instances of where the NPS signs or considers a designation to exist.  Examples; CA 180 is signed through Kings Canyon National Park and CA 120 is signed through Yosemite National Park.  Neither of those two segments is defined in the State's Route definition but it doesn't change the fact that the NPS clearly does it's own thing. 

[Scott5114]

I finally found my 1989 spreadsheet of US routes.

It does not count Yellowstone for US 20 at all (US 89 is also split; oddly, US 441's mileage through GSMNP is included).  The east segment is 2500 miles and the west segment is 865 miles for a total of 3365.

However, it counts all the US 20 Bus and US 20 ALT routes in these totals!

Subtracting these out gets an east segment of 2376 miles and a west segment of 861 miles for a total of 3237 miles (in 1989...freewayization in Iowa has likely shortened it a little more)

For US 6: 3249 miles for full list which includes all US 6 ALT, US 6 Bus, US 6 Byp and US 6N.

Was all of AASHTO/FHWA on cocaine for all of 1989 or something? Why the hell would you include bannered routes in a route's length??

[xonhulu]

Oregon chopped about 4 miles off US 20 when the Eddyville bypass opened in 2016.  I can't think of any other major changes to 20 out here in recent years.

I'm on the side of discounting any Yellowstone mileage.  Every official entity says US 20 doesn't exist there, so case closed, imo.

Having said that, I did see a US 212 shield posted in Yellowstone Park, a few miles inside the NE Entrance.  And I recall reading or hearing that the National Park Service actually maintains the Wyoming sections of US 212, the Beartooth Highway, even though it's outside the park.  I also remember seeing the NPS arrowhead logo on a highway maintenance station up towards Beartooth Pass, which is what made me curious in the first place.  This was over a decade ago, though, so it may no longer be the case.  Does anyone know the story there? 

[Max Rockatansky]

Oregon chopped about 4 miles off US 20 when the Eddyville bypass opened in 2016.  I can't think of any other major changes to 20 out here in recent years.

I'm on the side of discounting any Yellowstone mileage.  Every official entity says US 20 doesn't exist there, so case closed, imo.

Having said that, I did see a US 212 shield posted in Yellowstone Park, a few miles inside the NE Entrance.  And I recall reading or hearing that the National Park Service actually maintains the Wyoming sections of US 212, the Beartooth Highway, even though it's outside the park.  I also remember seeing the NPS arrowhead logo on a highway maintenance station up towards Beartooth Pass, which is what made me curious in the first place.  This was over a decade ago, though, so it may no longer be the case.  Does anyone know the story there?

The Northeast Entrance Road and the Grand Loop to the North Entrance are maintained all year. 

[Mapmikey]

I finally found my 1989 spreadsheet of US routes.

It does not count Yellowstone for US 20 at all (US 89 is also split; oddly, US 441's mileage through GSMNP is included).  The east segment is 2500 miles and the west segment is 865 miles for a total of 3365.

However, it counts all the US 20 Bus and US 20 ALT routes in these totals!

Subtracting these out gets an east segment of 2376 miles and a west segment of 861 miles for a total of 3237 miles (in 1989...freewayization in Iowa has likely shortened it a little more)

For US 6: 3249 miles for full list which includes all US 6 ALT, US 6 Bus, US 6 Byp and US 6N.

Was all of AASHTO/FHWA on cocaine for all of 1989 or something? Why the hell would you include bannered routes in a route's length??

They don't actually do that on the spreadsheet I have.  There is no grand total given and only state totals are shown (plus individual distances to the next US or Interstate route intersected), which do not include the bannered routes.   But including the bannered routes is the only way to get to the quoted distance of 3365 miles.

I have seen (but unable to find again) a pdf version of the 1989 list and do not remember if it gave a grand total.

Droz's old site had the total length of US 20 as 3237 miles and cites the 1989 log (so he did the same thing I did); Wikipedia quotes the 3365 figure and the source is somebody at FHWA.  There are no individual state ttoals on the page.

Droz had US 6 at 3208 miles as he didn't notice an error in the Nevada listing that doesn't separate a US 6 Business out correctly accounting for a few miles off my number.  Wikipedia has it at 3199 miles which is the sum of state distances it compiles with references.  It should be shorter than the 1989 total because of bypasses added and it is.

[CNGL-Leudimin]

I have one question. If you consider US 20 not to exist in Yellowstone, does that mean two separate instances of US 20 exist (and thus US 6 is indisputably the longest US Route)? Because, unlike e.g. I-35 which has two signed alternates each to bridge the Hillsboro-Denton and Burnsville-Lino Lakes sections, US 20 doesn't have any signed route between the East and West entrances.

[Scott5114]

Wikipedia quotes the 3365 figure and the source is somebody at FHWA.  There are no individual state ttoals on the page.

I've flagged it and opened a discussion on the talk page. Hopefully the data buffs will put together an accurate total from state DOT sources soon.

Where did you come across this spreadsheet, anyway?

I have one question. If you consider US 20 not to exist in Yellowstone, does that mean two separate instances of US 20 exist (and thus US 6 is indisputably the longest US Route)? Because, unlike e.g. I-35 which has two signed alternates each to bridge the Hillsboro-Denton and Burnsville-Lino Lakes sections, US 20 doesn't have any signed route between the East and West entrances.

This is an ecclesiastical question–do you consider there to be two separate US-2s, or is there one US-2 with a gap in the middle?