Interstate 580 Nevada

Interstate 580 and U.S. 395 are fully signed on their shared alignment between U.S. 50/William Street in Carson City and Interstate 80 in Reno. For the most part, both routes are signed side by side both on roadside reassurance markers such as this one in the Washoe Valley near Lake Washoe. Photo taken 10/05/12.


Interstate 580 begins at U.S. 50 in Carson City and extends north to meet Interstate 80 in Reno via the U.S. 395 freeway, which includes the Carson City Bypass, Washoe Lake Freeway, Interstate 580 Freeway Extension over Galena Creek, and Martin Luther King Jr. Memorial (North-South) Freeway in Reno. Until August 2012, the Interstate-standard segments of Interstate 580 were signed solely as U.S. 395, and Interstate 580 was a hidden designation (not signed). The completion of the freeway route between Washoe Lake and Mt. Rose Junction precipitated the signing of Interstate 580. The section of open freeway between Fairview Drive and U.S. 50 is not yet considered part of Interstate 580, but it will likely be added when the rest of the freeway is completed.

The 2002 FHWA Route Log and Finder's List officially recognizes Interstate 580 as extending between Neil Road (formerly Del Monte Lane) north to Interstate 80 Exit 15 via the U.S. 395 freeway. However, a 1984 letter agreement gives FHWA approval to additional segments of Interstate 580 freeway as it is constructed.1 With the completion of the Galena Creek/Pleasant Valley Bypass in August 2012, the entire route from Carson City to Reno was signed as Interstate 580 by early October 2012, with the exception of the short segment at the far southern end that is scheduled for completion in 2014.


Interstate 580 has been on the planning books since 1957. Interstate 580 has been part of Nevada's Interstate highway mileage just after the Interstate Highway System was designated in 1956. The first sections of the highway were opened in 1964 as part of U.S. 395; other segments followed in the early 1970s into the 1980s (see below). Construction of the Carson City Bypass and Galena Creek/Pleasant Valley Bypass ensued through the 2000s and into the early 2010s.

Reports from Jeff Royston indicate that Interstate 580 may have been briefly signed in Reno in the mid-1980s (around the same time Interstate 580 appeared on the Rand McNally Reno map and on the California State Automobile Association map), but whatever signs were place were removed or covered up by the 1990s. Interstate 580 was thus a "secret" Interstate (unsigned) through the 1990s and 2000s, with signs reemerging for Interstate 580 in 2012.

The Martin Luther King, Jr. Memorial Freeway (originally built as the North-South Freeway) carries Interstate 580 and U.S. 395 through Reno. This freeway, along with the Carson City Bypass and Pleasant Valley Bypass was constructed in phases according to the Interstate 580 Freeway Extension web page (click on "History & Overview"). The following provides opening dates for the freeway:

  • 1964-1970 - Segment from Alternate U.S. 395 and former Nevada 428 (Exit 44) at Lakeview north to Winters Ranch (near Exit 50, Alternate U.S. 395 and former Nevada 429) opened
  • 1973 - Segment from Nevada 648/Glendale Avenue (Exit 67) north to Business U.S. 395/Virginia Street at Panther Valley (Exit 72) opened
  • 1980 - Segment from Business U.S. 395 (Nevada 430)/South Virginia Street (Exit 63) north to Nevada 648/Glendale Avenue (Exit 67) opened
  • 1983 - Segment between Exits 61 and 63 (both Business U.S. 395/Virginia Street) opened
  • 1998 - Segment from Mt. Rose Junction (Nevada 431/Mt. Rose Highway and Nevada 341/Geiger Grade Road) (Exit 56) north to Business U.S. 395 (Nevada 430)/South Virginia Street (Exit 61) opened
  • February 16, 2006 - Segment from U.S. 50 and Nevada 530/East William Street northwest to Business U.S. 395 (Nevada 531)/North Carson Street opened (northern leg of Carson City bypass)
  • September 2009 - Segment from Fairview Drive (Exit 38) north to U.S. 50 and Nevada 530/East William Street (Exit 39) opened
  • August 24, 2012 and August 27, 2012 - Segment from Washoe Lake (near Bowers Mansion) (Exit 50) and Mt. Rose Junction (interchange with Nevada 431/Mount Rose Highway and Nevada 341/Geiger Grade Road) (Exit 56) opened,2 including the signature Galena Creek Bridge (1,700 feet long, 690 feet tall, "world's largest concrete cathedral arch bridge")3
  • August-October 2012 - Interstate 580 signs added along with U.S. 395 between Carson City and Reno4, 5
  • 2014 - anticipated completion date from U.S. 50-395/South Carson Street north to Fairview Drive

The project to fill the freeway gap between Washoe Lake and Mt. Rose Junction was primarily done because of safety concerns on Alternate U.S. 395 (Old Highway 395) through Pleasant Valley. Several fatal accidents occurred on this stretch of Old U.S. 395, and the freeway bypass places a barrier between the two directions of traffic.6 The highway is also anticipated to restore connectivity between the communities of Steamboat, Pleasant Valley, and Washoe City.

Highway Guides

Scenes Pertaining to Interstate 580

Interstate 580 Freeway Entrance Shield Assemblies
These Interstate 580 freeway entrance shield assemblies, which used to be posted as U.S. 395 until October 2012. These shields are posted at the Eastlake Boulevard interchange in Washoe Valley. Photos taken 10/05/12.

Signing Interstate 580

Until around August 7, 2012, Interstate 580 was an unsigned Interstate highway.4, 5 Prior to the announcement that Interstate 580 would become a signed route at that time, staff at AARoads had speculated about the legitimacy of the route number and whether it would ever become a signed route.

The first evidence we found of Interstate 580 in Reno was on a California State Automobile Association (CSAA) map of Reno in 1982. On that map, Interstate 580 was shown as marked as such along the U.S. 395 freeway between South Virginia Street and Interstate 80. Maps showed Interstate 580 as a marked, signed route for three or four years, including the 1985 Rand McNally map of Reno.

On September 16, 2002, Robert Herron wrote, "As for Interstate 580 signing in the past, there was signage briefly in the early 1980s for about one year. It was not co-signed with U.S. 395 on the freeway itself, just the approaches at the intersections. Signage at the Interstate 80 intersection and on the freeway never existed. Also it was on quite a few maps, up until the late 1980s. After one year, the approach signs had green blanks installed covering the Interstate 580 shields, leaving only U.S. 395 visible. I seem to remember a TV news story at the time that said that the rationale was that since Interstate 580 was only the section of freeway south of Interstate 80, and it was co-signed with U.S. 395 its entire length that it would lead to confusion. There is probably some truth to that because Interstate 515 is causing quite a bit of confusion in Southern Nevada. ... With the great source of pride this new freeway extension will be, and [since] NDOT always refers to the freeway as Interstate 580 in any media releases and internally (and politics), it appears Interstate 580 will be signed upon full completion in 2007-2008."

In addition, Jeff Royston wrote on August 17, 1998, "I know for a fact that Interstate 580 was signed as Interstate 580 Nevada. These signs were only on the approaches and not on the right of way. They were from S. Virginia Street to Mill Street. All Freeway Entrances had the Interstate 580 shield. If you go to the Mill Street overpass heading westbound, you will see a U.S. 395 green sign on the right and the Interstate 580 shield covered up with green sheeting. If you took off that green sheeting, you will probably find the Interstate 580 sign without "Nevada" on it. Another place that you can tell that they had an Interstate 580 sign is on Terminal Way, by the Airport. They have directional signs to US-395 and have blank spaces where the old Interstate 580 signs were."

So, by 1987, most maps ceased to show Interstate 580. The freeway was signed solely as U.S. 395. Many assumed that Interstate 580 had suffered the same fate as Interstate 580 in Omaha: deleted from the Interstate highway system. However, the Interstate 580 designation in Reno is alive and well, only hidden. Interstate 580 was the official designation of U.S. 395 from Neil Road (Del Monte Lane) north to Interstate 80. The only way a layperson would know that Interstate 580 still existed was by the white postmile markers, which show "IR 580."

Interstate 124 in Chattanooga is similar, with respect to U.S. 27. Ironically, these hidden Interstates are the opposite of hidden U.S. routes that run coincidentally with Interstates, such as U.S. 50 and U.S. 6 in Western Colorado and Eastern Utah. In the case of a short spur such as Interstate 705 in Tacoma, the highway does not carry more than one numbered route, so it would be posted as such.

In most cases, Interstate routes are owned by state governments. Whether or not an Interstate marker is posted, the state still gets Interstate funding. Different states seem to handle dual Interstate/U.S. number posting differently. AASHTO's policy on Interstate marking systems states that, "the U.S. Route numbers may be used in conjunction with Interstate Route markers where the U.S. Route leads into the Interstate Route, follows it for a 'reasonable distance,' and then departs again from the Interstate route."

Ed Wilson, retired Nevada DOT Customer Services Representative, added that the "general public remains more comfortable with the '395' moniker. Actually the proper designation seems to be important only to the FHWA, NDOT, land use planners, a few highway buffs, and such. Mr. and Mrs. America seem to just get confused with all the different letters and numbers, so we try to keep life simple for them."

Interstate 580 became well know the public when the bypass project between Washoe Lake and Mt. Rose Junction began, as the public website was called "I-580 Freeway Extension."7 With the completion of the final segment of freeway above Pleasant Valley in August 2012, Interstate 580 was fully signed with its own shields along with U.S. 395 by early October 2012.


  1. Spring 2012 Applications for AASHTO Special Committee on Route Numbering - parent site: AASHTO Special Committee on Route Numbering
  2. New I-580 Freeway Opening Date Announced by Pat Hambright, KOLO-TV Reno, August 14, 2012. Relevant quote: "NDOT tweeted on Tuesday that the southbound lanes of the new road will open August 24th, and the northbound lanes on August 27th."
  3. Gov. Brian Sandoval: I-580: The history -- and the promise by Governor Brian Sandoval, FOX-Reno News, August 14, 2012. Relevant quote: "The construction of the Galena Creek Bridge has generated positive local and national media attention to our region. At 1,700 feet in length, it has been billed as the world's largest concrete cathedral arch bridge -- an architectural marvel."
  4. I-580 Or US 395? by Terri Russell, KOLO-TV Reno, August 16, 2012. Relevant quote: "'Our I-580 goes from the Reno spaghetti bowl about 40 miles into Carson City. It will eventually end when we complete the Carson Freeway at the Spooner Summit Junction there on Highway 50. It is also 395. So the signs technically 580-slash 395,' says Scott Magruder with the Nevada Department of Transportation. I-580 signs have been going up all along the 395 corridor. Magruder says soon 395 markers will be placed along side. When the new roadway opens to Carson City it will be I-580 and US 395."
  5. New I-580's name explained by Dina Kupfer, NEWS 4 Reno KRNV-TV, August 7, 2012. Relevant quote: "I-580 is called an "interstate spur," meaning, it's built to interstate standards with a divided highway and limited access. Magruder says this helps for moving goods and services, and it makes for a safe highway. Once the new six lane highway from Mt. Rose Highway to Washoe Valley opens to traffic, the road through Pleasant Valley will be known as U.S. 395 Alternate."
  6. Gov. Brian Sandoval: I-580: The history -- and the promise by Governor Brian Sandoval, FOX-Reno News, August 14, 2012. Relevant quote: "According to NDOT, more than 40,000 vehicles use U.S. 395 every day, and a large percentage of those vehicles will use the new I-580 freeway once it opens to traffic. Tragically, since 1990 there have been more than a dozen fatalities on the current route, many caused by head-on collisions. Now, commuters will enjoy a divided highway, separated by a 4-foot high center median that will all but eliminate the possibility of a head-on collision. Additionally, as a result of Northern Nevada having an interstate freeway connecting Reno with the state's capital, residents living along the existing U.S. 395 highway will get their communities back. There will be less traffic passing through the valley during the morning and afternoon rush hours once the freeway officially opens to traffic in the next couple of weeks. Children, families and local drivers will be much safer."
  7. Interstate 580 Freeway Extension by Nevada DOT

Page Updated October 8, 2012.

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