List of Interstate Highways in Oregon

Interstate Highways of the Oregon Highway System
Interstate Highways of the Oregon Highway System
	Highway markers for Interstates in Oregon
	Interstate Highways highlighted in red
System information
	Maintained by ODOT
Formed	June 29, 1956
Highway names
Interstates	Interstate nn (I-nn)
US Highways	U.S. Route nn (US nn)
State	Oregon Route nn (OR nn)
Named highways	xx Highway No. nn
System links
	Oregon Highways; Interstate; US; State; Named; Scenic;

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]

^ McNichol (2006), p. 106.
^ 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.
^ 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.
^ McNichol (2006), pp. 10–11.
^ 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.
^ McNichol (2006), pp. 57, 121.
^ "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.
^ Cockle, Dick (September 21, 1988). "Final segment completes freeway system". The Oregonian. p. B4.

[mcnichol106-1] 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.

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