NDOT is changing exit numbers along I-580 starting this summer to coincide with I-580 mileage (the current numbering is based on the underlying US 395 statewide mileage starting from the CA border at Topaz Lake).
NDOT: Exit numbers on I-580 (https://www.nevadadot.com/safety/exit-numbers-on-interstate-580)
The webpage doesn't say it, but I'd hope NDOT is also going to install the green enhanced mileposts along all of I-580 to correspond with the new exit numbers. There's a few along the newest southern section of the Carson City Freeway, but that's it.
I'm actually not a fan, only because it will create an exit number gap at the Reno Spaghetti Bowl as I-580 ends while US 395 continues north from there. It's not a huge deal in the long term, but I always liked that the whole freeway had consistent exit numbers. This has been a situation unique to both of Nevada's Interstate spurs because the I-515 & US 95 overlap in Las Vegas/Henderson is the same way–the exit numbering is consistent along US 95 through the Vegas Spaghetti Bowl despite the I-515 terminus there. In both cases, the US route came first and the Interstate signed much later.
The rationale given for the change is "Federal guidelines require interstate exit numbers to reflect mileage specific to that corridor." I'm guessing they're citing the standard in MUTCD 2E.31 paragraph 16: "Where numbered routes overlap, continuity of interchange numbering shall be established for only one of the routes (see Figure 2E-21). If one of the routes is an Interstate and the other route is not an Interstate, the Interstate route shall maintain continuity of interchange numbering."
That's been a standard for a while...so why didn't NDOT renumber the freeway when the final link between Reno and Carson City was opened circa 2012? Maybe someone was researching exit numbering policies for the I-11 changeover down south and realized that I-580 was out of compliance with this standard...?
So the 2019 (and 2020) Rand McNally Road Atlases didn't goof when they showed the roadway's exits being numbered via Interstate 580's mileage instead of US 395's mileage. They just jumped the gun a little.
I'd argue that it's not really out of compliance as-is. I-580 is wholly concurrent with US 395 (unless they're planning on changing that?), and nothing says that the numbers have to start at 0 (see: I-276).
It seems like it would be more confusing to change the exit numbers now. And its particularly bad where a freeway has room to grow in the south or west direction. If the freeway were extended further down the corridor, would the numbers need to be changed again?
QuoteI'm actually not a fan, only because it will create an exit number gap at the Reno Spaghetti Bowl as I-580 ends while US 395 continues north from there.
I'm not a fan either; I think folks would find it terribly confusing. Will numbers suddenly jump as you cross I-80?
Quote from: mrsman on May 15, 2019, 10:16:06 PM
It seems like it would be more confusing to change the exit numbers now. And its particularly bad where a freeway has room to grow in the south or west direction. If the freeway were extended further down the corridor, would the numbers need to be changed again?
NDOT has no plans to extend I-580 West along US 50. And now that the US 395 corridor is not in contention for the future routing of I-11, extending the freeway south from Carson City is much less likely. But if they did, NDOT would need to renumber again.
Quote from: ClassicHasClass on May 15, 2019, 11:01:22 PM
QuoteI'm actually not a fan, only because it will create an exit number gap at the Reno Spaghetti Bowl as I-580 ends while US 395 continues north from there.
I'm not a fan either; I think folks would find it terribly confusing. Will numbers suddenly jump as you cross I-80?
Yes. Exit 36 (I-80, current exit 68) and exit 69 (Oddie Blvd) will be less than a mile apart.
Quote from: roadfro on May 16, 2019, 01:37:47 AM
Quote from: ClassicHasClass on May 15, 2019, 11:01:22 PM
QuoteI'm actually not a fan, only because it will create an exit number gap at the Reno Spaghetti Bowl as I-580 ends while US 395 continues north from there.
I'm not a fan either; I think folks would find it terribly confusing. Will numbers suddenly jump as you cross I-80?
Yes. Exit 36 (I-80, current exit 68) and exit 69 (Oddie Blvd) will be less than a mile apart.
Yeah, this stuff bothers me. Exit numbering should serve the 99.8% of the population that has no idea what "MUTCD" stands for. If NDOT is going to renumber from South Carson to Reno, they ought to continue the renumbering on US 395 all the way up to Bordertown at the NV/CA state line.
Quote from: gonealookin on May 16, 2019, 10:02:28 PM
If NDOT is going to renumber from South Carson to Reno, they ought to continue the renumbering on US 395 all the way up to Bordertown at the NV/CA state line.
But if they were to do that, then exit numbers would not match US 395 mileposting in any way (statewide or county-wide). I almost prefer there be a number gap.
Quote from: roadfro on May 16, 2019, 10:35:11 PM
Quote from: gonealookin on May 16, 2019, 10:02:28 PM
If NDOT is going to renumber from South Carson to Reno, they ought to continue the renumbering on US 395 all the way up to Bordertown at the NV/CA state line.
But if they were to do that, then exit numbers would not match US 395 mileposting in any way (statewide or county-wide). I almost prefer there be a number gap.
I get the technical point, of course, or I would never have found this forum in the first place. Just think the sequential numbering on the green signs should be more friendly to the general public. NDOT could still maintain the white paddles and the Highway Patrol might say on their radio "The crash is northbound 395 near Washoe 77" even if that's between green-sign Exit 48 and Exit 52 or whatever.
I think there should be an exception to the rule about signing mileposts (and by extension exit numbers) that's whenever an interstate highway totally within the realm of a single US highway route, the US highway route exit numbers will have precedence. This means that the exit numbers will follow 395, even though part of the road is also an interstate.
Nexus 5X
Quote from: mrsman on May 17, 2019, 12:23:58 AM
I think there should be an exception to the rule about signing mileposts (and by extension exit numbers) that's whenever an interstate highway totally within the realm of a single US highway route, the US highway route exit numbers will have precedence. This means that the exit numbers will follow 395, even though part of the road is also an interstate.
Nexus 5X
That would cause problems for roads like I-393. The current sequential numbers and mile-based numbers beginning at 0 are 1 are fine, but there's no point in using milage for US 4 or US 202.
Perhaps a miniature shield might be of use -- something to say "This is I-580 exit X" or "This is US-395 exit Y". This could also be done anywhere there's a multiplex and it might not be obvious which highway's exit numbers (or mileage) is being referenced.
Although I appreciate the sentiment, I think two exit numbers would end up being more confusing than one even if the one were discontinuous.
This is a work in progress. I had to drive up to Reno today and saw that the first four northbound I-580 exits in Carson City (up to Arrowhead Drive, which has a northbound exit only) and the final three southbound exits (starting with College Parkway) have been re-signed as Exits 3, 5, 6 and (as to Arrowhead Drive) 7.
Northbound, the first exit after Arrowhead Drive is across the line in Washoe County at Eastlake Blvd., and that's still signed as Exit 44 both northbound and southbound.
The first southbound exit in Carson City, Business 395/North Carson Street, is still signed Exit 43 for now. I guess that's because there are advance green, blue and brown signs on southbound 580 in Washoe County referencing Exit 43, so to avoid confusion it can't be re-signed as Exit 8 in Carson City until the same time those advance signs are changed.
Didn't realize this was going on, really just lends more to what I've said (or what my take is) previously; the corridor should be signed US 395 and I-580 should the silent Interstate designation.
This rule would cause extremely major problems for AZ if it is universally enforced. Not for I-19 because it's metric, but because of I-17 because it's lowest milepost is 194 at the southern terminus.
Quote from: Max Rockatansky on November 05, 2019, 08:19:08 PM
Didn't realize this was going on, really just lends more to what I've said (or what my take is) previously; the corridor should be signed US 395 and I-580 should the silent Interstate designation.
Agreed. This really shows how pointless the I-580 designation is on that stretch (the same could be said about I-515 down south).
I-515's days are numbered, but I-580's aren't near as I can tell, so they really ought to think it through more.
Would there be a violation of interstate numbering rules if the I -580 designation was extended northwest to the California border along with US 395? It would effectively be a "spur" of I-80 from the south (Carson City) and the north (California border). I-580 in California does something similar with I-80, with one spur going to San Rafael and another going to I-5, so it isn't that far of a stretch to see the same thing happen in Nevada.
Is there a reason why NDOT wouldn't apply to extend the I-580 designation north past I-80 all the way to the state line (as non-chargeable mileage)? I haven't been on that stretch in a while, but it seems like it meets design standards. That way, the the whole freeway section would have consistent numbering and there wouldn't be any confusion. (US-395 would continue to be co-signed, though).
Related question: was there any reason on picking I-580? Since I-580 in California is a major interregional route and not all that far away, it seems like it would have made more sense to pick another odd first digit, since 380, 780, and 980 in California are all shorter, more local routes, and 180 isn't even an interstate (and even further away). Just seems like they picked the number that would be most likely to cause confusion with a number in an adjoining state.
EDIT: I see I had the same idea as Concrete Bob within a minute of each other.
Wow !! What a coincidence. :bigass:
I-180 would have been amusing given how it can't be duplicated legislatively in California given CA 180 is a thing.
A possible explanation for the exit renumbering just occurred to me. When the latest leg of the Carson City Freeway opened, something I noticed then was the installation of green "enhanced reference location signs" (aka "the milepost signs that show shield and direction") on that project. It was circa 2015 that NDOT released their new policy for enhanced mileposts and reference location signs, but I think this 3-mile stretch of I-580 was the first time I saw the green ones used in Nevada.
Since then, it seems NDOT is (very gradually) going all in on the green enhanced reference location signs. Late September/early October, the current I-80 project in Reno (CA line to exit 12) got to the stage where new signs are going in. New white mileposts are installed, along with green enhanced reference location signs. (I haven't driven it, but I believe the I-11/Boulder City Bypass project also has these installed.)
So, if NDOT has a goal to put the green enhanced mileage signs along all interstates, then that forces them to make the exit numbering match on I-580.
Quote from: gonealookin on November 05, 2019, 08:01:09 PM
This is a work in progress. I had to drive up to Reno today and saw that the first four northbound I-580 exits in Carson City (up to Arrowhead Drive, which has a northbound exit only) and the final three southbound exits (starting with College Parkway) have been re-signed as Exits 3, 5, 6 and (as to Arrowhead Drive) 7.
Northbound, the first exit after Arrowhead Drive is across the line in Washoe County at Eastlake Blvd., and that's still signed as Exit 44 both northbound and southbound.
The first southbound exit in Carson City, Business 395/North Carson Street, is still signed Exit 43 for now. I guess that's because there are advance green, blue and brown signs on southbound 580 in Washoe County referencing Exit 43, so to avoid confusion it can't be re-signed as Exit 8 in Carson City until the same time those advance signs are changed.
Yeah, I saw this also when I had to drive to Carson City last month. NDOT did say that this would go forward in two separate projects...not sure why.
It looked to me like there might have been full BGS replacements on some of those signs in Carson City (some of those signs were 10+ years old). However, the SB signs for the Carson Street exit had been changed out not too long ago, so maybe those are being done via "greenouts" with the separate contract?
Quote from: wriddle082 on November 05, 2019, 09:06:21 PM
This rule would cause extremely major problems for AZ if it is universally enforced. Not for I-19 because it's metric, but because of I-17 because it's lowest milepost is 194 at the southern terminus.
I think it's more problematic that I-17's lowest milepost is 194...
Quote from: DTComposer on November 05, 2019, 10:48:35 PM
Is there a reason why NDOT wouldn't apply to extend the I-580 designation north past I-80 all the way to the state line (as non-chargeable mileage)? I haven't been on that stretch in a while, but it seems like it meets design standards. That way, the the whole freeway section would have consistent numbering and there wouldn't be any confusion. (US-395 would continue to be co-signed, though).
There are spots where it currently doesn't meet shoulder width standards (mainly northbound, from McCarran/Clear Acre to about Golden Valley, where they cheaply squeezed in an extra lane or merge lane at the expense of shoulders without having to widen bridges). But there is not a logical end point (population center or highway junction) for an interstate spur in that direction, so extending the I-580 designation north is unnecessary.
Quote from: DTComposer on November 05, 2019, 10:48:35 PM
Related question: was there any reason on picking I-580? Since I-580 in California is a major interregional route and not all that far away, it seems like it would have made more sense to pick another odd first digit, since 380, 780, and 980 in California are all shorter, more local routes, and 180 isn't even an interstate (and even further away). Just seems like they picked the number that would be most likely to cause confusion with a number in an adjoining state.
Well, there's a lot of mileage between the two 580s, so I don't think there's any real chance of confusion...
Keep in mind that Nevada's 580 has been on the books since the 1970's (and 515 too for that matter), and was only recently signed circa 2012. What also happened in the 1970's was Nevada's state route renumbering, which classified most urban routes with numbers in the 500-699 range. My hunch is that the "5" first digit was chosen to comply with the Interstate numbering for spurs while also giving these routes an "urban" number in the state system.
I-255 goes around the SE corner of metro St Louis. It becomes IL 255 when it heads north of I-270. The exit numbers restart at that point, going from 30 back down to 2. Nobody gets confused by this. I don't think many people pay much attention to exit numbers.
Quote from: skluth on November 06, 2019, 11:05:57 AM
I-255 goes around the SE corner of metro St Louis. It becomes IL 255 when it heads north of I-270. The exit numbers restart at that point, going from 30 back down to 2. Nobody gets confused by this. I don't think many people pay much attention to exit numbers.
They pay attention a lot more than you would think. They do look for their exit using that very number, and some of the smart ones, in states using distance-based numbering, figure out how far they have to go to their exit.
Quote from: 1 on May 17, 2019, 07:46:58 AM
Quote from: mrsman on May 17, 2019, 12:23:58 AM
I think there should be an exception to the rule about signing mileposts (and by extension exit numbers) that's whenever an interstate highway totally within the realm of a single US highway route, the US highway route exit numbers will have precedence. This means that the exit numbers will follow 395, even though part of the road is also an interstate.
Nexus 5X
That would cause problems for roads like I-393. The current sequential numbers and mile-based numbers beginning at 0 are 1 are fine, but there's no point in using milage for US 4 or US 202.
Then you might as well use no exit numbering at all for US-4 or US-202 as sequential exit numbering is pretty damned useless.
Quote from: Brandon on November 07, 2019, 01:35:49 PM
Quote from: 1 on May 17, 2019, 07:46:58 AM
Quote from: mrsman on May 17, 2019, 12:23:58 AM
I think there should be an exception to the rule about signing mileposts (and by extension exit numbers) that's whenever an interstate highway totally within the realm of a single US highway route, the US highway route exit numbers will have precedence. This means that the exit numbers will follow 395, even though part of the road is also an interstate.
Nexus 5X
That would cause problems for roads like I-393. The current sequential numbers and mile-based numbers beginning at 0 are 1 are fine, but there's no point in using milage for US 4 or US 202.
Then you might as well use no exit numbering at all for US-4 or US-202 as sequential exit numbering is pretty damned useless.
I-393, US 4, and US 202 are all overlapped here. The exits are coincidentally about a mile apart anyway.
Quote from: Brandon on November 07, 2019, 01:34:13 PM
Quote from: skluth on November 06, 2019, 11:05:57 AM
I-255 goes around the SE corner of metro St Louis. It becomes IL 255 when it heads north of I-270. The exit numbers restart at that point, going from 30 back down to 2. Nobody gets confused by this. I don't think many people pay much attention to exit numbers.
They pay attention a lot more than you would think. They do look for their exit using that very number, and some of the smart ones, in states using distance-based numbering, figure out how far they have to go to their exit.
I know people use them. I use them, especially when I'm driving long distance and need an easy way to remember how far I am from the border or where I should get gas. I just don't think they're very useful in urban situations. Again, not to say they don't have uses. They're just very limited.
Quelling the building stir-craziness from the past month of stay-at-home orders, I went for a long drive Friday which included I-580 northbound from Carson City to Reno. Made some observations which reminded me of this thread...Bumping to note that NDOT is finally making progress on this renumbering project.
From NDOT's Twitter feed on 4/23/2020:
(https://pbs.twimg.com/media/EWIqh6pUwAEfCjY?format=jpg&name=large)
I can report that exit numbers have been changed all the way up to the Mt Rose Hwy/SR 431 interchange as of 4/24/2020. In most cases, an overlay was used on the exit tabs or greenout panels applied over numbers on supplemental guide signs at interchanges–in several cases, the green color on the new exit panels didn't quite match the existing signs.
This photo though shows that some of the signs that had been recently replaced had overlays with the old number applied over the permanent sign with the new number.
Also noted that new green enhanced reference location signs have been installed up to the Mt Rose interchange where most of the stretch did not have them before, so I assume these are being installed concurrently with all the new exit numbers.