Interstate 184

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Interstate 184

Boise Connector
I-184 highlighted in red
Route information
Auxiliary route of I-84
Maintained by ITD
Length3.62 mi[1][2] (5.83 km)
HistoryCompleted in 1992
NHSEntire route
Major junctions
West end I-84 / US 30 in Boise
East end US 20 / US 26 in Boise
CountryUnited States
Highway system
  • Idaho State Highway System
SH-167 SH-200

Interstate 184 (I-184) is a short auxiliary Interstate Highway in Boise, Idaho, United States. It is a spur route of I-84 that connects the freeway to Downtown Boise, terminating at US Highway 20 (US 20) and US 26 on the west side of the Boise River.

The western section of the freeway, named the Boise Connector, opened to traffic in December 1968. It was designated as I-180N until a renumbering of I-84 that was approved in 1979. I-184 was extended to a new interchange with US 20 and US 26 in 1992 as part of a new Downtown Boise connector and bridge.

Route description

Westbound on I-184 from Orchard Street near Downtown Boise

I-184, also known as the Boise Connector or just the "Connector", is a short, six-lane urban freeway that travels between a junction with I-84 and the west side of Downtown Boise.[3] Its western terminus is the "Flying Wye" interchange with I-84 and US 30 in southwestern Boise, which includes a braided ramp for adjacent exits on both freeways.[3][4] I-184 travels northeast and crosses over a spur railroad near an interchange with Franklin Street on the south side of the Boise Towne Square shopping mall. The freeway then intersects Curtis Road near the Saint Alphonsus Regional Medical Center and turns due east along Fairview Avenue, which acts as a frontage road. On the west side of the Boise River in Rotary Park, I-184 terminates after an interchange with US 20 and US 26, which serve northwestern Boise and Garden City on Chinden Boulevard. US 20 and US 26 supersede I-184 and cross into Downtown Boise, where they split into the paired one-way Front and Myrtle streets.[3][5]

I-184 is the only auxiliary Interstate Highway in Idaho and the state's shortest, at 3.62 miles (5.83 km).[3] The highway is maintained by the Idaho Transportation Department (ITD), which conducts an annual survey of traffic on certain highway segments that is expressed in terms of annual average daily traffic (AADT), a measure of traffic volume for any average day of the year. The sole traffic recording device on I-184, tracking eastbound traffic near Cole Road, reported a daily average of 78,034 vehicles on the highway in 2022.[6] From 2015 to 2022, traffic volumes increased by 3 percent—slower than other area roads—and congestion is typically worse near the Flying Wye interchange during the evening rush hour.[7] According to the ITD, the average speed of traffic on the freeway in 2022 was 66 miles per hour (106 km/h), above the posted speed limit of 60 miles per hour (97 km/h).[8][9]


The Boise Connector was planned in the early 1960s to connect the Boise freeway bypass to Downtown Boise and its inner neighborhoods.[10] One version of the plan proposed a full loop bisecting Downtown Boise to carry I-80N, but it was rejected in favor of a less costly spur route.[11] The westernmost section of the connector, including a sprawling wye interchange with I-80N, began construction in July 1965 and cost $9.5 million to build.[12] It was opened to traffic on December 12, 1968, a year before the rest of the bypass,[3][13] and initially terminated at Garden Street.[14]

Interstate 180N

NHSEntire route

The freeway was numbered Interstate 180N (I-180N) until October 13, 1979, when I-184 was adopted to match I-84, which was planned to succeed I-80N effective May 1, 1980.[15][16] It was the only signed suffixed auxiliary Interstate Highway in the nation.[3] Parts of the connector were signed as part of State Highway 55 (SH-55)[17] until it was realigned onto Eagle Road in September 1990.[18][19] Eastbound traffic on US 30 was also used a section of I-180N before merging onto Main Street and Fairview Avenue.[20] This concurrency was eliminated in 1980, when US 30 was relocated onto I-84.[21][22]

Construction of the Broadway–Chinden Connector, which would connect I-184 with downtown Boise, began in January 1988 and cost $60 million to complete.[23] The new bridge across the Boise River was opened on August 7, 1992, replacing a pair of smaller bridges to the north.[24] The westernmost segment of I-184, including the Flying Wye interchange, was rebuilt from 1999 to 2004 to accommodate an additional set of lanes.[10] The project cost $86 million[25] (equivalent to $133 million in 2023[26]) and was delayed approximately six months due to financial constraints and delays in bridge construction in the initial phase of the project.[27]

Exit list

The entire route is in Boise, Ada County.

I-84 west (US 30 west) – Nampa
Western terminus; I-84 exit 49
I-84 east (US 30 east) – Mountain Home
Westbound exit and eastbound entrance; serves Boise Airport
1.081.741AFranklin Road
1.332.141BCole RoadWestbound exit and eastbound entrance
2.544.092Curtis RoadWestbound exit also signed as "Fairview Avenue"
3Fairview AvenueWestbound access is part of exit 2
US 20 / US 26 east
No access to US-20/US-26 west; continuation as freeway beyond eastern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ a b "Milepoint Log: Interstate 184" (PDF). Idaho Transportation Department. January 25, 2016. Retrieved July 19, 2018.
  2. ^ "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. January 27, 2022. Retrieved August 13, 2022.
  3. ^ a b c d e f "Interstate 184 – Idaho". Idaho Transportation Department. May 2006. Archived from the original on September 1, 2010. Retrieved June 21, 2018.
  4. ^ Wagner, Morgan (January 15, 2016). "Find yourself in a crash along the Flying Wye? Look for the color codes!". KBOI. Retrieved July 19, 2018.
  5. ^ Google (August 26, 2021). "Interstate 184" (Map). Google Maps. Google. Retrieved August 26, 2021.
  6. ^ "Automatic Counter Volumes: County #226 - Emerald". Idaho Transportation Department. January 2023. Retrieved February 12, 2023.
  7. ^ Teres-Martinez, Andrea (August 15, 2022). "These are the Boise area's 10 busiest highways. Is your commute on one of them?". The Idaho Statesman. Archived from the original on August 16, 2022. Retrieved February 12, 2023.
  8. ^ "Annual Speed Distribution for 2022: I-84 .5 mi. NE of N. Cole OP (EB)" (PDF). Idaho Transportation Department. January 9, 2023. Retrieved February 12, 2023.
  9. ^ Harding, Hayley (May 23, 2020). "COVID-19 shutdowns have led to fewer people on the roads — and much higher speeds". The Idaho Statesman. Retrieved February 12, 2023.
  10. ^ a b Wyatt, Liz (February 7, 1999). "Rebuilding the Wye interchange". Idaho Statesman. p. 15A.
  11. ^ "The Roads Not Taken: Boise and the Interstate Highway, 1960". Boise State University Library. Archived from the original on May 23, 2011. Retrieved July 22, 2018.
  12. ^ "Rites Mark Dedication Of Boise West Connector". The Idaho Statesman. December 12, 1968. p. 1. Retrieved February 6, 2023 – via
  13. ^ Quintana, Craig (August 11, 1999). "Idaho delegates pressure EPA to call air clean". The Idaho Statesman. pp. 1A, 11A. Retrieved February 16, 2023 – via
  14. ^ "Engineering Firm Named To Design Interchanges". The Idaho Statesman. November 27, 1965. p. 14. Retrieved February 6, 2023 – via
  15. ^ Special Committee on U.S. Route Numbering (October 13, 1979). "Route Numbering Committee Agenda Showing Action Taken by the Executive Committee" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. p. 1. Retrieved July 19, 2018 – via Wikimedia Commons.
  16. ^ "Interstate 80N to change name to Interstate 84 in Idaho, Oregon". The Idaho Statesman. April 2, 1980. p. 8C. Retrieved February 7, 2023 – via
  17. ^ "Officials Tour Boise West Connection Prior to Rites". The Idaho Statesman. December 9, 1968. p. 20. Retrieved February 6, 2023 – via
  18. ^ "Regular Meeting of the Idaho Transportation Board, October 17–19, 1990" (PDF). Idaho Transportation Department. October 18, 1990. p. 66. Retrieved February 10, 2023.
  19. ^ LaMay, Colleen (September 18, 1990). "Eagle gears for traffic from new I-84 exit". The Idaho Statesman. p. 3C. Retrieved February 10, 2023 – via
  20. ^ Boise South Quadrangle (Topographic map). 1:24,000. United States Geological Survey. 1972. Retrieved February 10, 2023.
  21. ^ Special Committee on U.S. Route Numbering (June 22, 1980). "Route Numbering Committee Agenda Showing Action Taken by the Executive Committee" (Report). Washington, DC: American Association of State Highway and Transportation Officials. p. 514. Retrieved February 11, 2023 – via Wikisource.
  22. ^ 1979 Rural Traffic Flow Map, State of Idaho (Map). Idaho Transportation Department. 1979. Retrieved February 11, 2023.
  23. ^ Ensunsa, David (January 19, 1988). "Part of Garden Street to close Wednesday". The Idaho Statesman. p. 3C. Retrieved February 10, 2023 – via
  24. ^ "Drivers ease on down Boise's new roadway". The Idaho Statesman. August 8, 1992. p. 1A. Retrieved February 10, 2023 – via
  25. ^ Sewell, Cynthia (December 2, 2005). "State to unveil landscaping options for the Wye". The Idaho Statesman. p. 1A. Retrieved February 16, 2023 – via
  26. ^ Johnston, Louis; Williamson, Samuel H. (2023). "What Was the U.S. GDP Then?". MeasuringWorth. Retrieved November 30, 2023. United States Gross Domestic Product deflator figures follow the MeasuringWorth series.
  27. ^ Kolman, Joe (June 11, 2004). "Flying Wye work just about done". Idaho Department of Transportation. Archived from the original on June 24, 2021. Retrieved June 19, 2021.

External links

Media related to Interstate 184 at Wikimedia Commons