Interstate 380 forms a long freeway spur leading northwest from I-80 as part of the multi-state Avenue of the Saints corridor (Iowa 27). I-380 joins the cities of Iowa City, Cedar Rapids and Iowa City in east central Iowa. Coupled with U.S. 218 & Iowa 27, the interstate forms a seamless expressway route south to Mount Pleasant, the Keukuk area and ultimately St. Louis, Missouri.
A full cloverleaf interchange joins Interstate 80 with U.S. 218 & Iowa 27 (Avenue of the Saints) on the western outskirts of Iowa City. Interstate 380 begins there, with the trio leading north by the growing suburb of North Liberty to cross Coralville Lake (Iowa River). A rural stretch ensues northward to the Linn County line, where industrial parks appear through the south side of Cedar Rapids.
Interstate 380 & Iowa 27 (Avenue of the Saints) parts ways with U.S. 218 at the U.S. 30 & 151 freeway running across the south side of Cedar Rapids. Continuing north, I-380 & IA 27 become more urban through the viaduct leading to the Cedar River. This stretch of freeway forms an ess curve as it spans the river east to run between Downtown and the Quaker Oats factory. Speed limits on this section are set at 55 miles per hour, with automated enforcement by the city of Cedar Rapids via speed cameras positioned to the south near 3rd Avenue SW and to the north near H Avenue. Four sets of cameras were installed in 2010. Iowa DOT ruled that two of the assemblies must be disabled or removed in March 2015, stating that there was no safety rationale for their use.1 They remained in operation as of March 2016 due to an ongoing appeal filed by the city. The threshold for receiving a citation is 12 miles over the posted limit of 55 MPH.2
Advancing north from central Cedar Rapids, I-380 & IA 27 remain a busy route to the city of Hiawatha north of Iowa 100 to leave the main built up area beyond Robins. The freeway becomes rural again to Center Point, a bedroom community in northern Linn County, and the ensuing drive through Benton and Buchanan Counties.
Interstate 380 & Iowa 27 combine with the U.S. 20 freeway east of Raymond and Evansdale as they enter the Waterloo area. The trio run concurrently for approximately 5.7 miles to a split just west of the Cedar River. Iowa 27 and the Avenue of the Saints corridor remain west along U.S. 20 to Iowa 58 to bypass central Waterloo while U.S. 218 returns to overlap with Interstate 380 for the final two mile spur into the city. I-380 formally ends at the at-grade intersection of U.S. 218 (Washington Street) and Mitchell Avenue.
U.S. 218 extends northward from the I-380 terminus along a divided boulevard to a separate freeway linking Downtown with Cedar Falls (and the Avenue of the Saints corridor) to the northwest. There are no plans to join these two sections of highway presently, though ample right of way exists between Hawthorne Avenue and the freeway beginning at 6th Street.
The Interstate 380 designation was initially applied by AASHO to the Des Moines urban loop along side Interstate 235. The I-380 overlap was removed by AASHO on November 10, 1958.3
Interstate 380 was established by AASHTO from I-80 north to Waterloo via Cedar Rapids on June 23, 1969. It appears the number 380 was selected instead of 180 to offset duplication with Iowa 180, a former state route linking Hayesville with Iowa 149 in Keokuk County.
The freeway opened in stages, starting in 1973 and finishing 1985. The following list provides the opening dates for the freeway:4
- Interstate 80 north to Exit 13 (CR E70) in Cedar Rapids: September 19, 1973
- Exit 13 to U.S. 30-151-218 (Lincoln Freeway): June 25, 1976
- U.S. 30-151-218 Lincoln Freeway to 5th Avenue SW: December 15, 1976
- 5th Avenue SW to 8th Street NE: June 11, 1979
- 8th Street NW to Glass Road: December 4, 1981
- Glass Road to Boyson Road: November 17, 19825
- Hiawatha to Iowa 150 near Urbana: August 14, 19845
- Iowa 150 to U.S. 20: September 12, 19855
- U.S. 20 to Mitchell Avenue: August 9, 19845