Is there a two-digit interstate duplex longer than I-20/59? Also, what are the longest 2-digit US highway duplexes?
I believe 80/90 is longer. There is also 90/94 in Indiana/Illinois and again in Wisconsin, part of which is in fact 39/90/94.
Yeah, it looks like I-80/I-90 in Indiana and Ohio is longer.
80/90: 277 miles
20/59: 152 miles
90/39: 97 miles
90/94(WI): 93 miles
80/90 is definitely the winner as far as interstates go. US routes... that's a trickier question. There are plenty of significant duplexes out west, but which is longest? Requiring that both routes be 2 digits eliminates several candidates, at least.
US route duplexes I can think of:
US 1 and 23 between Jacksonville, FL and north of Alma, GA - 106 miles
US 14 and 16 between Ucross, WY and Moorcroft, WY - 111 miles
US 20 and 26 between Vale, OR and Mountain Home, ID - 113 miles
US 19 and 98 between Perry, FL and Chassahowitzka, FL - 127 miles
US 20 and 26 between Shoshoni, WY and east of Douglas, WY - 160 miles
US 85 and 87 (not sure how well this one is signed) from Raton, NM to I-25 Exit 185 near Castle Rock, CO - 194 miles
A couple of historic ones:
US 60 and 70 between Beaumont, CA and Globe, AZ - 400 miles
US 6 and 50 between Ely, NV and Grand Junction, CO - 470 miles
US 70 and 99 between Los Angeles, CA and Indio, CA (also with I-10) - 127 miles
US 40 and 95 from west of Lovelock, NV to Winnemucca, NV - 96 miles
Some other long ones-
US-30 and 287 from Rawlins to Laramie, 111 miles
US 14 and 16 from Ucross WY to Moorcroft WY - 111 miles
US 54 and 400 from Augusta KS to Mullinville KS - 148 miles
US 50 and 400 from the west side of Dodge City KS to Granada CO- 134 miles
US 56 and 412 from Springer NM to Boise City OK- 126 miles
US 64 and 412 from Clayton NM to Guymon OK- 106 miles
US 6 and 34 from Hastings NE to Culbertson NE- 142 miles
The US 62-412 overlap is about 150 miles long.
Quote from: TheStranger on May 23, 2010, 12:57:29 PM
A couple of historic ones:
US 40 and 95 from west of Lovelock, NV to Winnemucca, NV - 96 miles
When US 95 was extended through Nevada around 1940, it originally followed US 40 all the way to Fernley before doubling back to Fallon (on what is now US 50 Alt) -- this overlap was originally around 130 miles.
The current alignment, which bypasses Fernley by heading directly south to Fallon (at the Trinity junction southwest of Lovelock), was in place by 1960 and is about 95 miles.
Several more:
US 6 and 50 between Ely, NV and Delta, UT - 153 miles
US 6 and 50 (and I-70) between Green River, UT and Grand Junction, CO - 106 miles
US 14, 16 and 20 from Pahaska, WY to Greybull, WY - 103 miles
US 16 and 20 from Pahaska, WY to Worland, WY - 141 miles
US 26 and 87 (and I-25) between Casper, WY and I-25 Exit 92 - 96 miles
US 59 and 71 between Texarkana, AR and Mena, AR - 102 miles
US-60 and US-70 were, back in the day, multiplexed between Globe, AZ and Banning, CA. The distance is about 406 miles, if you take the Box Canyon Road alignment of US-60/70 east of Mecca. It was shortened to about 396 miles around 1938 using an alignment that is essentially underneath I-10 all the way to the modern western terminus of US-60 east of Quartzsite.
Part of that route was also shared with US-80, US-89 (both around Phoenix, US-80 for a longer distance) and US-99 (in California)
Quote from: agentsteel53 on May 23, 2010, 09:08:41 PM
US-60 and US-70 were, back in the day, multiplexed between Globe, AZ and Banning, CA. The distance is about 406 miles, if you take the Box Canyon Road alignment of US-60/70 east of Mecca. It was shortened to about 396 miles around 1938 using an alignment that is essentially underneath I-10 all the way to the modern western terminus of US-60 east of Quartzsite.
Part of that route was also shared with US-80, US-89 (both around Phoenix, US-80 for a longer distance) and US-99 (in California)
The US 60/70/80/89 co-routing from Phoenix to Queen Valley was about 55 miles (probably the longest four-US route concurrency ever), with 80/89 continuing south from Queen Valley to Florence and Tucson along today's AZ 79, and 80 continuing west from Phoenix to today's AZ 85 along Buckeye Road.
US 60/70/89 continued in from Wickenburg east to Queen Valley, so approximately 109 miles of all three of them running together; in the midst of all that, AZ 93 continued from Wickenburg to AZ 87 in Mesa for 70 miles of it running with 60/70/89.
US 60/70/80/89 and AZ 93 ran together for about 16 miles from Phoenix to Mesa, probably one of the more notable five-route concurrencies that ever existed.
Quote from: TheStranger on May 23, 2010, 09:30:33 PM
US 60/70/80/89 and AZ 93 ran together for about 16 miles from Phoenix to Mesa, probably one of the more notable five-route concurrencies that ever existed.
There is a US 56-64-287-412/OK 3 quintuplex in the Oklahoma panhandle.
Quote from: bugo on May 23, 2010, 10:17:41 PM
Quote from: TheStranger on May 23, 2010, 09:30:33 PM
US 60/70/80/89 and AZ 93 ran together for about 16 miles from Phoenix to Mesa, probably one of the more notable five-route concurrencies that ever existed.
There is a US 56-64-287-412/OK 3 quintuplex in the Oklahoma panhandle.
You're forgetting the venerable Boise City Traffic Circle--six highways at once!
(//www.aaroads.com/shields/img/OK/OK20010561i3.jpg)
(image courtesy Jake)
I don't think they are signed, but since all of the state and US highways going through Indianapolis were moved to the I-465 loop, there are a bunch of different multiplexes at different points on I-465. If I read things correctly on the map, it appears that the most is between Exits 46 and 47 where 8 routes(I-465, US 31, US 36, US 40, US 52, US 421, IN 37 and IN 67) are all multiplexed. This I would guess is probably the most highways multipexed on any stretch of highway in the country.
If we're sticking to two-digit concurrencies though, I think the Phoenix examples might be the historic largest/lengthiest...
Though if you think abut it, 3duses tend to function as 2dis do.
Quote from: Bickendan on May 24, 2010, 03:15:40 PM
Though if you think abut it, 3duses tend to function as 2dis do.
Currently, yes. In the 1925 plan, it seems as though they were meant to be short connecting routes much unlike the US-395 or US-191 of today.
Quote from: Brandon on May 24, 2010, 04:07:34 PM
Quote from: Bickendan on May 24, 2010, 03:15:40 PM
Though if you think abut it, 3duses tend to function as 2dis do.
Currently, yes. In the 1925 plan, it seems as though they were meant to be short connecting routes much unlike the US-395 or US-191 of today.
Looking at Robert Droz's page on the earliest number assignments...
http://www.us-highways.com/1927us.htm
the longest 3-digit US route was US 212 (at 474 miles) with no 3dus route extending for more than three states - something which has drastically changed over time.
U.S. 19/41 share pavement from northwest Atlanta to the southside of Griffin, just north of the Pike-Spalding County line. This is a distance of about 45 miles, give or take.
Be well,
Bryant