Interstate 39 (I-39) is a north–south Interstate Highway in Illinois and Wisconsin that runs from an interchange at I-55 in Normal, Illinois, to State Trunk Highway 29 (WIS 29) approximately south of Wausau, Wisconsin. In total, Interstate 39 is long. In Illinois, the route has a total length of ; in Wisconsin, I-39 has a length of .
Among the newest Interstate Highways in Illinois, I-39 was completed in 1992. Designed to replace U.S. Route 51 (US 51) with an Interstate-grade freeway, the highway runs concurrently with US 20 in Rockford before joining I-90. From Rockford to Portage, Wisconsin, I-39 and I-90 run concurrently. From Madison to Portage, I-94 joins the two; at , the three-way concurrency is the longest in the country. From Portage northward, US 51 rejoins I-39, and the Interstate uses its mileposts northward.
Route description
Illinois
left|thumb|Aerial view of I-39 as it passes [[Minonk, Illinois, April 2012]]
In Illinois, I-39 begins at I-55 north of Bloomington–Normal, Illinois, less than one mile east from the intersection of I-74 and I-55 that runs around the city of Normal. US 51 splits from I-55, joining I-39; exit 2 marks the northern terminus of the US 51 business route. From Normal northward, I-39 runs northward largely through rural areas. At exit 8, the route forms the southern terminus of Illinois Route 251 (IL 251), which was derived from the original routing of US 51.
In Oglesby in central LaSalle County, I-39 passes next to Starved Rock State Park, the busiest state park in Illinois. North of the park, it crosses the Illinois River over the Abraham Lincoln Memorial Bridge; at long, it is the longest bridge in the state. Just north of the river, I-39 passes between the cities of LaSalle and Peru; as it intersects I-80 and US 6, it makes its southernmost connections with the Chicago region. North of I-80, the wind turbines of the Mendota Hills Wind Farm (the first commercial wind farm in Illinois) can be seen from milepost 72 at Mendota north to near Paw Paw. As I-39 continues northward, I-39 also intersects US 52 and US 30.
In Ogle County, I-39 intersects with I-88 (IL 110), connecting I-39 to both Chicago and the Quad Cities regions. As it intersects IL 38, IL 64, and IL 72, I-39 connects with the DeKalb–Sycamore region and far west suburbs of the Chicago area.
As I-39 crosses into Winnebago County, the Baxter Road exit (exit 115) is the final exit before I-39 joins the US 20 freeway bypass in Rockford. Approximately a mile east of the Alpine Road/US 20 interchange, I-39 joins US 20, moving from nearly entirely farmland to medium-density populated areas.
After heading northeast for approximately , US 20 splits from I-39/US 51; a mile northward, I-39/US 51 runs concurrently with I-90 (Jane Addams Memorial Tollway). Though signed as I-39/I-90, the concurrency follows the mileposts of I-90. Though I-39 itself is not tolled, the Illinois Tollway collects tolls on the I-90 portion, including two ramp interchanges and an open-road toll plaza between Rockton and South Beloit.
At exit 1 (IL 75) in South Beloit, US 51 splits from I-39 to join IL 75; westward, it continues the route of IL 251 into Wisconsin. For all but one mile that I-39 is in Illinois, it runs concurrently with US 51.
Wisconsin
left|thumb|I-39/US 51 in northern Wisconsin
thumb|Northern terminus of I-39 at the interchange with WIS 29 near Wausau
I-39 enters Wisconsin in Rock County, concurrently with I-90. Bypassing Beloit to the east, it passes underneath the County Trunk Highway P bridge (CTH-P, Stateline Road). The tri-stack exit 185 provides access to Beloit through WIS 81 and serves as the southern terminus of I-43 (accessing Milwaukee and Green Bay). The northernmost interchange serving the Beloit region is CTH-S (Shopiere Road) at exit 183. About north of the I-43 interchange, I-39/I-90 is joined by WIS 11 for as it bypasses Janesville. In addition to the northern interchange that holds WIS 11, Janesville is also accessed by US 14 and WIS 26 (Milton Avenue). After crossing the Rock River, I-39/I-90 has an interchange with WIS 59, connecting it with Edgerton (to the west) and Milton (to the southeast). further north, the highway has an interchange with US 151 (splitting Madison and Sun Prairie); the northernmost Madison-area I-39 interchanges are US 51 (Madison and DeForest) and WIS 19 (Sun Prairie and Waunakee); CTH-V (West North Street) for DeForest serves as the last Dane County exit.
I-39/I-90/I-94 enters Columbia County north-northwest of CTH-V.
In the late 1960s and early 1970s, a major supplemental freeway system plan was proposed, with the goal of providing Illinois residents access to freeways within 30 minutes or less. One of the proposed routes, FAP 412, was a route that would extend from US 20 in Rockford to I-57 just north of Salem, similar to the earlier requested route. Due to traffic counts, only the portion between Rockford and Decatur was prioritized.
Over the course of the 1970s, planning for the US 51 supplemental freeway took place in earnest. However, debate ensued over what type of highway should be built. The Illinois Department of Transportation (IDOT) wanted the entire highway built to Interstate Highway standards, but a transportation committee established to review the proposed supplemental freeway system recommended only Interstate construction between Rockford and I-80. The highway from Oglesby south to Decatur was recommended to be an at-grade expressway, utilizing the existing road where possible. After a decade of lobbying by interest groups, it was announced in 1986 that US 51 would be rebuilt to Interstate standards from Oglesby to Normal. However, due to funding concerns and local opposition, it was decided that the Bloomington to Decatur segment would not be built to Interstate standards; this segment was made a four-lane expressway.
The first segment of the freeway opened 1984 from IL 5 (now I-88) in Rochelle, to US 20 in Rockford. When the freeway was completed south from IL 5 to I-80 in 1986, IDOT officially requested an Interstate designation for the new highway, and I-39 was officially designated.<!--There should be a better source for this. WP:USRD/AASHTO should have AASHTO's approval of the number which can be cited with Template:AASHTO minutes.--> By December 1987, construction on the section of I-39 between I-80 and IL 251 was finished. The next section, between IL 251 and I-55 in Bloomington–Normal, was completed by 1992, although this stretch of the highway was opened in several phases as completed. In December 1989, the section from Bloomington–Normal to Hudson opened, a distance of about . In early September 1992, another segment opened from IL 116 north to IL 17.
Wisconsin
In Wisconsin, the highway was officially designated in 1992. In October 1993, the American Association of State Highway and Transportation Officials (AASHTO) established part of I-39 in its northern section between Rockford and Rib Mountain, Wisconsin, then designated I-39 along existing portions of I-90, I-94, and US 51. However, this part of the highway was not marked as I-39 for another four years, primarily because the Wisconsin Department of Transportation (WisDOT) had to reconstruct the interchange connecting I-90 and I-94 with WIS 78 near Portage. The remaining segment along I-90/I-94 was not signed for I-39 until late 1998. The designation of I-39 violated Wisconsin's rule of not having any state trunk highway number duplicated—Interstate, US, or state—as WIS 39 already existed.
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See also
References
External links
- Illinois Highway Ends: Interstate 39