Interstate 184 Explained

State:ID
Type:I
Route:184
Spur Type:I
Spur Of:84
Alternate Name:Boise Connector
Map Custom:yes
Map Notes:I-184 highlighted in red
Length Mi:3.62
Length Ref:[1] [2]
Established:1968
History:Completed in 1992
Direction A:West
Terminus A: in Boise
Direction B:East
Terminus B: in Boise
Counties:Ada
Previous Type:SH
Previous Route:167
Next Type:SH
Next Route:200

Interstate 184 (I-184) is a short auxiliary Interstate Highway in Boise, Idaho, United States. The only auxiliary Interstate in Idaho, 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

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]

I-184 is the only auxiliary Interstate Highway in Idaho and the state's shortest, at 3.62miles.[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.[5] 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.[6] According to the ITD, the average speed of traffic on the freeway in 2022 was 66mph, above the posted speed limit of 60mph.[7] [8]

History

The Boise Connector was planned in the early 1960s to connect the Boise freeway bypass to Downtown Boise and its inner neighborhoods.[9] 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.[10] 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.[11] It was opened to traffic on December 12, 1968, a year before the rest of the bypass,[3] [12] and initially terminated at Garden Street.[13]

State:ID
Type:I
Header Type:former
Route:180N
Established:1968
Decommissioned:1980
Location:Boise

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.[14] 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)[15] until it was realigned onto Eagle Road in September 1990.[16] [17] Eastbound traffic on US 30 was also used a section of I-180N before merging onto Main Street and Fairview Avenue.[18] This concurrency was eliminated in 1980, when US 30 was relocated onto I-84.[19]

Construction of the Broadway–Chinden Connector, which would connect I-184 with downtown Boise, began in January 1988 and cost $60 million to complete.[20] The new bridge across the Boise River was opened on August 7, 1992, replacing a pair of smaller bridges to the north.[21] The westernmost segment of I-184, including the Flying Wye interchange, was rebuilt from 1999 to 2004 to accommodate an additional set of lanes.[9] The project cost $86 million[22] (equivalent to $ in) and was delayed approximately six months due to financial constraints and delays in bridge construction in the initial phase of the project.[23]

Notes and References

  1. Web site: January 25, 2016 . Milepoint Log: Interstate 184 . . July 19, 2018.
  2. Web site: January 27, 2022 . Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways . FHWA Route Log and Finder List . . August 13, 2022.
  3. Web site: May 2006 . Interstate 184 – Idaho . Idaho Transportation Department . dead . https://web.archive.org/web/20100901075514/http://www.itd.idaho.gov/50.Years/I-50_I_184.html . September 1, 2010 . June 21, 2018.
  4. News: Wagner . Morgan . January 15, 2016 . Find yourself in a crash along the Flying Wye? Look for the color codes! . . July 19, 2018.
  5. Web site: January 2023 . Automatic Counter Volumes: County #226 - Emerald . Idaho Transportation Department . February 12, 2023.
  6. News: 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 . https://archive.today/20220816162256/https://www.idahostatesman.com/news/local/traffic/article264089051.html . August 16, 2022 . February 12, 2023.
  7. Web site: January 9, 2023 . Annual Speed Distribution for 2022: I-84 .5 mi. NE of N. Cole OP (EB) . Idaho Transportation Department . February 12, 2023.
  8. News: Harding . Hayley . May 23, 2020 . COVID-19 shutdowns have led to fewer people on the roads — and much higher speeds . The Idaho Statesman . February 12, 2023.
  9. News: Wyatt . Liz . February 7, 1999 . Rebuilding the Wye interchange . 15A . Idaho Statesman.
  10. Web site: The Roads Not Taken: Boise and the Interstate Highway, 1960 . . dead . https://web.archive.org/web/20110523141255/http://library.boisestate.edu/Special/Interstate.shtm . May 23, 2011 . July 22, 2018.
  11. News: December 12, 1968 . Rites Mark Dedication Of Boise West Connector . 1 . The Idaho Statesman . Newspapers.com . February 6, 2023.
  12. News: Quintana . Craig . August 11, 1999 . Idaho delegates pressure EPA to call air clean . 1A, 11A . The Idaho Statesman . Newspapers.com . February 16, 2023.
  13. News: November 27, 1965 . Engineering Firm Named To Design Interchanges . 14 . The Idaho Statesman . Newspapers.com . February 6, 2023.
  14. News: April 2, 1980 . Interstate 80N to change name to Interstate 84 in Idaho, Oregon . 8C . The Idaho Statesman . Newspapers.com . February 7, 2023.
  15. News: December 9, 1968 . Officials Tour Boise West Connection Prior to Rites . 20 . The Idaho Statesman . Newspapers.com . February 6, 2023.
  16. Web site: October 18, 1990 . Regular Meeting of the Idaho Transportation Board, October 17–19, 1990 . 66 . Idaho Transportation Department . February 10, 2023.
  17. News: LaMay . Colleen . September 18, 1990 . Eagle gears for traffic from new I-84 exit . 3C . The Idaho Statesman . Newspapers.com . February 10, 2023.
  18. 1972 . Boise South Quadrangle . Topographic map . United States Geological Survey . 1:24,000 . February 10, 2023.
  19. 1979 . 1979 Rural Traffic Flow Map, State of Idaho . Idaho Transportation Department . February 11, 2023.
  20. News: Ensunsa . David . January 19, 1988 . Part of Garden Street to close Wednesday . 3C . The Idaho Statesman . Newspapers.com . February 10, 2023.
  21. News: August 8, 1992 . Drivers ease on down Boise's new roadway . 1A . The Idaho Statesman . Newspapers.com . February 10, 2023.
  22. News: Sewell . Cynthia . December 2, 2005 . State to unveil landscaping options for the Wye . 1A . The Idaho Statesman . Newspapers.com . February 16, 2023.
  23. News: Kolman . Joe . June 11, 2004 . Flying Wye work just about done . dead . https://web.archive.org/web/20210624201002/https://apps.itd.idaho.gov/Apps/MediaManagerMVC/NewsClipping.aspx/Preview/1621 . June 24, 2021 . Idaho Department of Transportation . June 19, 2021.