I-19: the Metric Interstate

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Big Nick
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I-19: the Metric Interstate

Post by Big Nick »

The USA is known for being very non-metric in road terms. But they do have an Interstate that is measured and signed in a definitely non-Imperial manner!
https://www.atlasobscura.com/places/i19 ... interstate
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Re: I-19: the Metric Interstate

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It's not the only example, I had to do a doubletake on the I-265 at Louisville https://www.google.com/maps/@38.2881612 ... 312!8i6656
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Re: I-19: the Metric Interstate

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I-19 was experimental I believe and I'm under the impression it will revert to "English" measurements when signs are replaced due to non-compliance with MUTCD.

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Re: I-19: the Metric Interstate

Post by Truvelo »

It was still metric in 2013 when I took this. I've just noticed it has button copy too. Presumably the sign will be patched with 2 mi instead of a complete replacement as it looks to be good condition. Maybe the rougher signs will be replaced though.
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Re: I-19: the Metric Interstate

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No doubt President Trump's supporters will see the signs as un American and have them replaced. I'm surprised someone hasn't destroyed the kilometre signs already as being some un American, communist plot.
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Re: I-19: the Metric Interstate

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Truvelo wrote: Fri Sep 14, 2018 18:53 It was still metric in 2013 when I took this. I've just noticed it has button copy too. Presumably the sign will be patched with 2 mi instead of a complete replacement as it looks to be good condition. Maybe the rougher signs will be replaced though.
The problem does not lie with the "3 km" part of the sign, but the the "Exit 95" part of the sign - exit numbers are the distance in kilometres (miles elsewhere in the US) from the start of the freeway. Changing the freeway back to miles would result in all maps having to be changed and also business cards and letterheads which give relevant exit numbers.
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Re: I-19: the Metric Interstate

Post by Euan »

I suppose kilometre distance numbered junctions do have the advantage of not needing to use the suffix notation for junction numbers whenever a new junction is added or the motorway is extended from the end where the junction numbering starts.
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Re: I-19: the Metric Interstate

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Euan wrote: Sun Sep 16, 2018 10:46 I suppose kilometre distance numbered junctions do have the advantage of not needing to use the suffix notation for junction numbers whenever a new junction is added or the motorway is extended from the end where the junction numbering starts.
Other problems exist though; e.g. if the road is diverted and is longer/shorter; the numbers will no longer be correct if the new route is shorter/longer.

Also, where multiple exits occur in the same km/mile a suffix is required to differentiate them.
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Re: I-19: the Metric Interstate

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c2R wrote: Sun Sep 16, 2018 17:18
Euan wrote: Sun Sep 16, 2018 10:46 I suppose kilometre distance numbered junctions do have the advantage of not needing to use the suffix notation for junction numbers whenever a new junction is added or the motorway is extended from the end where the junction numbering starts.
Other problems exist though; e.g. if the road is diverted and is longer/shorter; the numbers will no longer be correct if the new route is shorter/longer.

Also, where multiple exits occur in the same km/mile a suffix is required to differentiate them.
Maybe in some urban areas where the junctions are frequent there may be a pair of junctions within a 1km of each other. Even then 1km is quite a tight space between junctions, but it probably depends on the size and design of the junctions involved. I presume the centre of the junction is normally used as the point of reference in determining the number of kilometres along the motorway.
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Re: I-19: the Metric Interstate

Post by Truvelo »

Suffixes are also used where junctions have more than one exit slip. Cloverleafs for example will have exits A and B with the same number.
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Re: I-19: the Metric Interstate

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c2R wrote: Sun Sep 16, 2018 17:18
Euan wrote: Sun Sep 16, 2018 10:46 I suppose kilometre distance numbered junctions do have the advantage of not needing to use the suffix notation for junction numbers whenever a new junction is added or the motorway is extended from the end where the junction numbering starts.
Other problems exist though; e.g. if the road is diverted and is longer/shorter; the numbers will no longer be correct if the new route is shorter/longer.

Also, where multiple exits occur in the same km/mile a suffix is required to differentiate them.
Kilometres have an advantage over miles as it is less likely to have two exits wihthin a kilometre of each other compared to within a mile of each other. That said, if an interchange has two separate slip roads such as here, they are denoted as "A" and "B" respectively.
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Re: I-19: the Metric Interstate

Post by J N Winkler »

Bryn666 wrote: Fri Sep 14, 2018 12:01I-19 was experimental I believe and I'm under the impression it will revert to "English" measurements when signs are replaced due to non-compliance with MUTCD.

JN Winkler is the man to ask.
Sorry to jump in this thread late (and thanks for the kind words, Bryn). At the moment the initiative to return I-19 to English units appears to have stalled due to community opposition. There is little appetite to change exit numbers and the metric signs themselves are seen as a tourist attraction. A few years ago, Arizona DOT carried out a descoped version of the originally planned sign replacement that renewed exit direction signs (which have arrows with no distances) but did not touch signs with explicit distance expressions other than ones north of the SR 86 Ajo Way interchange. The metric signing originally extended all the way to the I-10 interchange, but was cut back south to SR 86 (with no change in exit numbers) when a 2004 project upgraded the I-10 connection to the present three-level wye.

Arizona DOT now has a portal for old construction as-builts and all of the I-19 signing plans are available through it.

https://road.azdot.gov/

The key ones are as follows:

* I-19-1(81)--installed the original metric signs (explicit units of m and km only on advance guide signs)

* H260701C, H260702C--1999 replacement of the original 1981 metric signs (explicit units of m and km on interchange sequence signs as well as advance guide signs)

* H774101C--the recent descoped sign replacement

Within the US, Arizona has long had a reputation as hostile terrain for Hispanics. Although it was never part of the Deep South, Arizona was what was called a "preclearance" state for voting rights purposes because of a history of making it difficult for Hispanics to vote. Ironically enough, the original I-19 metric signing called not just for use of the units system favored south of the border, but also English/Spanish bilingual signs, and a Spanish-language version of the then standard Arizona welcome sign ("Bienvenidos a Arizona--El Estado del Gran Cañon"). Some but not all of these signs have since been replaced in kind.
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Re: I-19: the Metric Interstate

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J N Winkler wrote: Thu Oct 25, 2018 19:10 Within the US, Arizona has long had a reputation as hostile terrain for Hispanics. Although it was never part of the Deep South, Arizona was what was called a "preclearance" state for voting rights purposes because of a history of making it difficult for Hispanics to vote. Ironically enough, the original I-19 metric signing called not just for use of the units system favored south of the border, but also English/Spanish bilingual signs, and a Spanish-language version of the then standard Arizona welcome sign ("Bienvenidos a Arizona--El Estado del Gran Cañon"). Some but not all of these signs have since been replaced in kind.
As with many southern states demographic changes have greatly increased the percentage of those with Hispanic origins in Arizona. In 2010 the largest ancestral groups in order were Mexican, German, English, Irish and Native American. The Hispanic influence is largest in the big cities such as Phoenix and Tucson.

Tucson is still predominantly white but the ethnic mix has changed enormously since 1970. Like Miami an increasing percentage of the white population are retirees attracted by the climate while a lot of the Hispanic population is made up of a younger people. By the time the next census takes place it is expected that Hispanic population will be the largest group.

Interstate signage is an interesting subject because a major justification for the establishment of the Interstate system was related to Defence and the US Army adopted metric standards in 1918. The Sunday name for the enabling legislation was The National Interstate and Defense Highways Act. Ask an US army soldier how far it is to the next town and you will get an answer in form of 10 klicks where a klick is 1 km. Numbering the junctions was however left to the States.

Connecticut, Delaware, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont use a similar system to that in the UK as exits are numbered sequentially which causes much the same issues as they do here when new junctions are added so I-95 in Massachusetts has Junctions 1, 2A, 2B, 3 , 4 , 5 , 6A, 6B etc. All interchanges in Massachusetts were supposed to be renumbered to mileage-based numbers under a project scheduled to start in 2016 but that has now been postponed indefinitely !
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Re: I-19: the Metric Interstate

Post by J N Winkler »

KeithW wrote: Sat Oct 27, 2018 10:34Connecticut, Delaware, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont use a similar system to that in the UK as exits are numbered sequentially which causes much the same issues as they do here when new junctions are added so I-95 in Massachusetts has Junctions 1, 2A, 2B, 3 , 4 , 5 , 6A, 6B etc. All interchanges in Massachusetts were supposed to be renumbered to mileage-based numbers under a project scheduled to start in 2016 but that has now been postponed indefinitely !
The current edition of the MUTCD, which was last updated in 2009, calls for all exit numbering to be distance-based and for exit numbering to be provided on non-Interstates. This has created interesting problems and compliance is far from full.

* Some of the northeastern states, where exits tend to be closely spaced (e.g. I-95 in Connecticut), have attempted to obtain waivers on the basis that current exit numbers are "close enough" to hypothetical mileage-based exit numbers. FHWA has so far been unwilling to entertain such requests.

* States like New York already have mileage-based numbering on certain routes and are slowly converting others as part of sign rehabilitation contracts. I-84 (sign updating contract advertised last summer) is the latest. Back in the 1970's, NYSDOT planned to convert sequential exit numbers to distance-based, but held off because conversion to metric signs was deemed imminent (as part of the 1970's metric push) and it did not want to incur the expense of a two-step conversion from sequential to mileage-based and then mileage-based to kilometer-based. In terms of current MUTCD requirements, the New York Thruway Authority is expected to be the final holdout, because its sequential numbering is long established, familiar to regular users, and relatable to toll tickets that will remain in use until full AET is adopted. Moreover, the Thruway mainline is milepointed counting up from New York City west to the Pennsylvania state line, which is the exact opposite of the MUTCD milepointing standard.

* Immediate compliance with the requirement to number exits on non-Interstates has, in states like North Carolina, resulted in exit numbers being added to brief freeway segments on long state and US highways for which other relocations are planned. This is expected to result in nominally distance-based exit numbers that are inconsistent with true mileage from route origin/south or west boundary of the state (e.g., Exit 504 on US 64 will not actually be 504 miles from the state line along US 64). The choice then becomes one of living with the inconsistency (as Arizona does with I-10, whose routing in Phoenix had not been settled at the time exit numbering was rolled out on Interstates in 1970; I-10 in Arizona is 2 1/4 miles longer than originally projected and exit numbers east of Phoenix are therefore 2 miles lower than they should be) or fixing it through an exit renumbering (as Utah DOT did with I-15 about fifteen years ago).

* Some states, like Kansas, are ignoring the requirement to number exits on non-Interstates. (Kansas was among the last to fall in compliance with the original requirement to number exits on Interstates.)

* Other states, like Texas and Arizona, have instituted non-Interstate distance-based exit numbering with zero points chosen on an ad hoc basis (US 75 in Dallas, US 59 in Houston), or have keyed it to a statewide milepointing/location reference system that diverges from MUTCD requirements in key respects. In Texas, SH 130 east of Austin has exit numbers that correspond to the distance from the latitude of the north edge of the Texas Panhandle (not the Red River), and thus increase from north to south. Meanwhile, in Arizona the origin milepoint of a given route that starts away from the state line is not zero but rather the milepoint of its parent route at the point where the two routes intersect, and exit numbers are determined accordingly.

FHWA has announced its intent to revise the MUTCD in the near future, so I don't expect further progress on meeting the 2009 requirements at least until state DOTs and other agencies have a chance to review the proposed changes. A rulemaking document is anticipated for 2019, but I will be mildly surprised if that deadline is met.
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Re: I-19: the Metric Interstate

Post by mikehindsonevans »

Fascinating - thank you for the details of this aspect of your country.
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