List of Interstate Highways in Oregon

Interstate Highways of the Oregon Highway System
Interstate 5 marker
Interstate 84 marker
Interstate 205 marker
Highway markers for Interstates in Oregon
Map
Interstate Highways highlighted in red
System information
Maintained by ODOT
FormedJune 29, 1956 (1956-06-29)[1]
Highway names
InterstatesInterstate nn (I-nn)
US HighwaysU.S. Route nn (US nn)
StateOregon Route nn (OR nn)
Named highwaysxx Highway No. nn
System links

The Interstate Highways in Oregon are the segments of the national Dwight D. Eisenhower System of Interstate and Defense Highways[2] that are owned and maintained by the U.S. state of Oregon. On a national level, the standards and numbering for the system are handled by the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO), while the highways in Oregon are maintained by the Oregon Department of Transportation (ODOT).

These highways are built to Interstate Highway standards,[3] meaning they are all freeways with minimum requirements for full control of access, design speeds of 50 to 70 miles per hour (80 to 115 km/h) depending on type of terrain, a minimum of two travel lanes in each direction, and specific widths of lanes or shoulders;[4] exceptions from these standards have to be approved by the FHWA.[5] The numbering scheme used to designate the Interstates was developed by AASHTO, an organization composed of the various state departments of transportation in the United States.[6]

The Oregon state government initially proposed numbering the auxiliary Interstates using lettered suffixes, but were denied in 1958 by the American Association of State Highway Officials (forerunner to the AASHTO).[7] The last section of the Interstate Highway system to be built in Oregon, on I-82 near Hermiston, opened on September 20, 1988.[8]

Primary Interstate Highways

Number Length (mi)[9] Length (km) Southern or western terminus Northern or eastern terminus Formed Removed Notes
I-5 308.14 495.90 I-5 at the California state line I-5 at the Washington state line 01957-01-011957 current
I-80N 375.17 603.78 I-5 / US 30 in Portland I-80N at the Idaho state line 01957-01-011957 01980-01-011980 Renumbered to I-84
I-82 11.01 17.72 I-82 at the Washington state line I-84 / US 30 in Umatilla County 01957-01-011957 current
I-84 375.17 603.78 I-5 / US 30 in Portland I-84 at the Idaho state line 01980-01-011980 current
  •       Former

Auxiliary Interstate Highways

Number Length (mi)[10] Length (km) Southern or western terminus Northern or eastern terminus Formed Removed
I-105 3.49 5.62 OR 99 / OR 126 / OR 126 Bus. in Eugene I-5 / OR 126 in Springfield 01957-01-01c. 1957 current
I-205 26.07 41.96 I-5 in Tualatin I-205 at the Washington state line 01958-01-011958 current
I-305 Salem I-5 in Salem 01957-01-01c. 1957 01967-01-011967
I-405 3.53 5.68 I-5 in Portland I-5 / US 30 in Portland 01958-01-011958 current
I-505 US 30 in Portland I-405 / US 30 in Portland 01957-01-01c. 1957 01988-01-011988
  •       Former

References

  • McNichol, Dan (2006). The Roads that Built America. New York: Sterling. ISBN 1-4027-3468-9.
  • Kramer, George. "Interstate 50th Anniversary: The Story of Oregon's Interstates" (PDF). Compiled by Oregon Department of Transportation. Oregon Department of Transportation. Archived from the original (PDF) on December 15, 2006. Retrieved August 31, 2016.
  • Staff (May 2004). "The Interstate Highway System in Oregon: A Historic Overview" (PDF). Oregon Department of Transportation.[permanent dead link]
  1. ^ McNichol (2006), p. 106.
  2. ^ Swift, Earl (2011). The Big Roads: The Untold Story of the Engineers, Visionaries, and Trailblazers Who Created the American Superhighways. Boston: Mariner. p. 5. ISBN 978-0-547-90724-6.
  3. ^ Lewis, Tom (2013). Divided Highways: Building the Interstate Highways, Transforming American Life (Updated ed.). Ithaca, NY: Cornell University Press. p. 253. ISBN 978-0-8014-7822-2.
  4. ^ McNichol (2006), pp. 10–11.
  5. ^ Zander, Mark, ed. (September 19, 2013). "Chapter 11: Design, Section 44: Interstate Highways" (PDF). Facilities Development Manual. Wisconsin Department of Transportation. p. 2. Archived from the original (PDF) on April 16, 2014. Retrieved April 14, 2014.
  6. ^ McNichol (2006), pp. 57, 121.
  7. ^ "Correspondence, A. E. Johnson and W. C. Williams". American Association of State Highway Officials. May 15, 1958. pp. 1–2. Retrieved April 2, 2021 – via AASHTO Route Numbering Archive.
  8. ^ Cockle, Dick (September 21, 1988). "Final segment completes freeway system". The Oregonian. p. B4.
  9. ^ Adderly, Kevin (January 27, 2016). "Table 1: Main Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of December 31, 2015". Route Log and Finder List. Federal Highway Administration. Retrieved August 31, 2016.
  10. ^ Adderly, Kevin (January 27, 2016). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of December 31, 2015". Route Log and Finder List. Federal Highway Administration. Retrieved August 31, 2016.
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