Interstate 43 (I-43) is a 191.55-mile-long (308.27 km) Interstate Highway located entirely within the U.S. state of Wisconsin, connecting I-39/I-90 in Beloit with Milwaukee and I-41, U.S. Highway 41 (US 41) and US 141 in Green Bay. Wisconsin Highway 32 (WIS 32) runs concurrently with I-43 in two sections and US 41, US 45, I-94, I-894, US 10, WIS 57, and WIS 42 overlap I-43 once each. There are no auxiliary or business routes connected to I-43; however, as of late 2015 there is a signed alternate route in Milwaukee County.
I-43 highlighted in red
|Maintained by WisDOT|
|Length||191.55 mi (308.27 km)|
|Lake Michigan Circle Tour|
|South end||I-39 / I-90 / WIS 81 in Beloit|
|North end||I-41 / US 41 / US 141 in Howard|
|Counties||Rock, Walworth, Waukesha, Milwaukee, Ozaukee, Sheboygan, Manitowoc, Brown|
I-43 came about as a result of toll road proposals that included a Milwaukee to Superior corridor that included Hurley, Wausau and Green Bay. Only the Milwaukee-to-Green Bay section was approved. The route was originally planned to follow an alignment about midway between US 41 and US 141 (the latter paralleled Lake Michigan at the time) along WIS 57. Controversy about this location and use of right-of-way led to the establishment of the current alignment, which follows much of what was the 1950s-era realignment of US 141 from Milwaukee to Sheboygan, and a new alignment from Sheboygan to Green Bay. This section was completed in 1981.
The Beloit-to-Milwaukee segment was developed after two separate proposals for Interstates, one of them between Milwaukee and Beloit and the other between Milwaukee and Janesville. The Milwaukee–Beloit route was chosen, completed in 1976 as WIS 15 and renumbered as I-43 in 1988. To connect the two segments, I-43 was signed concurrently with the east–west segment of I-894 and the north–south portion of I-94 in the greater Milwaukee metropolitan area from I-894 to the Marquette Interchange, which was completely reconstructed with work being completed in 2008.
Wisconsin had anticipated the Interstates with studies of possible toll roads. When the original Interstate system was approved the state was only given two routes: I-90 and I-94. The Wisconsin Transportation Commission submitted a request to add an Interstate in 1953 connecting Milwaukee to Green Bay, a request the federal government denied. The commission, after a study by Wisconsin Turnpike Commission—which was established in 1953—submitted a request in 1963 for a route that connected Milwaukee and Superior by way of Green Bay, Wausau, Hurley and Ashland which could be completed in increments. However, only the Milwaukee-to-Green Bay segment was approved. The original plan for the northern part of I-43 was to locate it midway between US 141 and US 41, using most of the current alignment of WIS 57 north of WIS 33 in Saukville; additionally, it was proposed to use the Interstate 57 number, though that was changed due to resistance from Illinois to extend its portion through Chicago. But farmers and landowners within the corridor opposed the plan. According to the opponents of the I-43 construction, what the commission revealed as their plan to construct I-43 along the WIS 57 corridor did not reveal that instead of using the existing right-of-way, the freeway was to be built 2.25 miles (3.62 km) west of WIS 57. This was the case despite the fact that WIS 57 had a wide right-of-way of 300 feet (91 m). Protests, including farmers bringing their cows to graze on the Wisconsin State Capitol grounds, prompted a compromise to utilize the freeway built for US 141 between Milwaukee and Sheboygan instead, building the remaining freeway for the Interstate itself. This plan, particularly the new freeway, met resistance from the Brown, Sheboygan, and Manitowoc county governments. Construction first began in 1963 on the freeway that was at the time designated US 141. The first segment to begin construction was a 3.4-mile (5.5 km) segment beginning at the Port Washington Road exit in Milwaukee County. An additional 10 miles (16 km) of the highway were completed in Ozaukee County by 1964. In 1965, a 9.3-mile (15.0 km) bypass of Sheboygan opened to traffic. The last major segment, consisting of 94.4 miles (151.9 km) of roadway, was started in 1972 after the last of these governments, Manitowoc County, pledged its support. The portion in Milwaukee County extending from the Port Washington Road exit to the Marquette Interchange was completed in 1981 to open the route.
The southwestern portion has also had a history of requests for Interstate routings. Interstate routings for such a connection between Beloit and the Milwaukee metropolitan area were requested by the Wisconsin Department of Transportation (WisDOT) but denied by the Federal Highway Administration (FHWA) in 1973. Another request for a link to Janesville was also denied. Despite the denials, local and state officials continued to seek funding to construct a freeway between these two metropolitan areas. A government collaboration called the "Highway 15 Committee" was formed to present and promote the route. Construction began on the route in the 1960s with the first segment, a 0.9-mile (1.4 km) connector linking US 45 with I-894 as part of the project to build the Hale Interchange connecting the pending route with I-894. The new connector received the US 45 designation as that highway was transferred onto the freeway heading north. The first long segment was completed in 1969. It extended from the US 45 connector to CTH-F (now WIS 164) in Big Bend. After this segment was opened, the WIS 15 designation was applied. The next segment, to East Troy, was opened in 1972, the year the Highway 15 Committee had hoped the route would be completed in its entirety. It was extended to Elkhorn in 1973 in conjunction with the US 12 freeway construction, then to I-90 in 1976. I-43 signs were placed on the freeway by 1988 after designation in 1987, replacing WIS 15. I-43 was also mapped concurrently with I-94 and I-894 to link the two segments together.[self-published source?] Even though exit number tabs were labeled according to the new mileposts, the mileposts themselves were not renumbered to coincide with the current length until 1991.
The Marquette Interchange, which connects I-43 with I-94,and I-794, was completely reconstructed over a four-year span, beginning in October 2004 and ending in September 2008. This project eliminated left-hand exits and widened connecting ramps between I-94 and I-43.
I-43 begins in Rock County as the eastern leg of a cloverleaf interchange with I-39/I-90 just east of Beloit. The highway becomes WIS 81 west of the interchange. The Beloit-to-Milwaukee segment of I-43 passes mainly through farmland situated on rolling hills, going around urbanized areas except for in the greater Milwaukee area—where the route passes through residential suburban zoning with some embedded industrial establishments. The Interstate bypasses Clinton to the north at WIS 140 and passes into Walworth County five miles (8.0 km) east of WIS 140. Daily traffic counts as of 2007 for Rock County range from 12,400 to 19,200 with the higher counts closest to Beloit. The interchange with I-39/I-90 accommodates 1,000–5,200 vehicles daily, with the most traffic on ramps connecting southbound I-39/I-90 to westbound WIS 81 and westbound I-43 to southbound I-39/I-90. I-43 passes north of Darien and crosses US 14 at that point, then junctions with WIS 50 south of Delavan. About 14,000–19,200 vehicles use this section daily as of 2006.
In Elkhorn, I-43 junctions with WIS 67, US 12, and WIS 11. The freeway passes through East Troy about 10 miles (16 km) northeast of Elkhorn and junctions with WIS 20 and WIS 120. It then enters Waukesha County at Mukwonago. I-43 crosses WIS 83 at an interchange just southeast of the village. After about eight miles (13 km), the highway junctions with WIS 164 just north of Big Bend, and then enters the city of New Berlin where the freeway has interchanges with South Racine Avenue (CTH-Y) and South Moorland Road (CTH-O). It then turns east to enter Milwaukee County. Traffic volumes range from 21,000 (as of 2006) around Elkhorn to 35,800 (as of 2006) in Waukesha County to 85,000 (2007 figures) at WIS 100.
The Beloit-to-Milwaukee portion (at the Hale Interchange with I-894) was given the name "Rock Freeway," named because the freeway traverses Rock County and heads towards the cities in the Rock River valley, including Rockford, Illinois. However, the moniker generally only applies to the portion of the route in Waukesha and Milwaukee counties;[self-published source?] freeway names in southeastern Wisconsin media are used interchangeably with Interstate numbers. The freeway is entirely four lanes from Beloit to New Berlin. A six-lane segment begins where US 45 merges on the Interstate.
I-43 connects with US 45 south and WIS 100 at South 108th Street. US 45 joins the highway for one mile (1.6 km), then turns northward onto I-894 west and I-41/US 41 south at the Hale Interchange, while I-43 follows I-894 east and I-41/US 41 south along the Airport Freeway into Greenfield, (forming a wrong-way concurrency with I-41) with interchanges with WIS 24, WIS 36 and WIS 241. At the Mitchell Interchange, I-894 ends and I-41/I-94/US 41 continues south while I-43 turns north to follow I-94 northbound, also known as the North–South Freeway, into downtown Milwaukee where it meets I-794 at the Marquette Interchange. The Airport Freeway carries 107,000–134,000 vehicles per day (as of 2007). The freeway between the Mitchell and Marquette Interchanges carried less at that time—97,000 (closer to downtown) to 105,000 The highway passes through mixed urban residential/industrial areas of the greater Milwaukee area, carrying six lanes throughout with the exception of near the Marquette Interchange where eight lanes of traffic exist.
I-43 continues north from the Marquette Interchange, while I-94 turns westward. After passing through downtown Milwaukee, just east of Marquette University, It crosses US 18 at Highland Boulevard and crosses WIS 145 at the McKinley Boulevard/Fond du Lac Avenue interchange. Exit 72C's northbound off and on ramps in downtown Milwaukee pass underneath the county courthouse via tunnels to Kilbourn Avenue. On the way north out of Milwaukee, The Interstate passes through Glendale, junctioning with WIS 190 (Capitol Drive) and WIS 57 (Green Bay Ave), and north of Good Hope Road has a grassy median with a cable barrier. WIS 100 and WIS 32 connect at Brown Deer Road and WIS 32 follows the Interstate north into Ozaukee County.[self-published source?] Up to 146,000 vehicles used this portion daily in 2007. This count decreased further north—with a count of 78,900 vehicles per day near WIS 100's northern terminus and 69,600 closer to the Ozaukee County border. As it passes through mixed residential and commercial zones north of downtown, the highway carries eight lanes of traffic downtown, six lanes of traffic north of North Avenue to Bender Road, and four lanes of traffic north of Bender road all the way to Green Bay.
WIS 57 joins the freeway three miles (4.8 km) north of the county line in Mequon at the junction of WIS 167. The urban residential areas thin out north of this point as a mix of farmland and forest begins to dominate. WIS 60 terminates in Grafton at the Interstate seven miles (11 km) further north and WIS 32 turns off toward Port Washington one mile (1.6 km) north of WIS 60. WIS 33 crosses the route in Saukville, Wisconsin. WIS 57 turns north off the freeway, which turns eastward to go around Port Washington to the north. WIS 32 rejoins the freeway on the north side and the two routes follow the Lake Michigan shoreline northeast into Sheboygan County. WIS 32 leaves the freeway at Cedar Grove and the Interstate passes Oostburg to the east and Sheboygan to the west. In Sheboygan, I-43 interchanges with WIS 28, WIS 23, and WIS 42. I-43 enters Manitowoc County nine miles (14 km) north of Sheboygan. Traffic counts in southern Ozaukee County peak at 66,900 vehicles per day (as of 2007), this value generally decreases further north. The counts in Sheboygan County bottom out at 21,100 vehicles per day (as of 2005) just south of the Manitowoc County line.
I-43 passes Cleveland on the county line. The highway continues to follow the lakeshore to straddle Manitowoc's rapidly developing west side, passing west of Newton, Wisconsin, with a weigh station for southbound truck drivers located midway between Newton and Cleveland. I-43 connects with US 151 and WIS 42. WIS 42 north follows the freeway north to the interchange with US 10. WIS 42 leaves to the east along with US 10 east, and US 10 west follows I-43 north to the interchange with WIS 310 where it turns off to the west. The Interstate passes Francis Creek and Maribel (at WIS 147) and turns northwestward into Brown County, with a rest stop located just before the county line. I-43 in Manitowoc County has the least traveled portion of the highway with 17,400 vehicles passing south of WIS 147 according to 2005 results. These values increase further south.
The Interstate passes Denmark and meets the terminus of WIS 96 one mile (1.6 km) north of the county line. the Interstate then continues another seven miles (11 km) to Bellevue where US 141 begins. This interchange provides access to WIS 29, a route the freeway crosses under later. At this point, the Interstate enters urban residential areas as it approaches Green Bay. I-43 junctions with WIS 172 in Allouez then turns northeast to bypass Green Bay to the east, passing under the aforementioned WIS 29. After turning northwestward, the Interstate interchanges with WIS 54 and WIS 57 and crosses the Fox River on the Leo Frigo Memorial Bridge, passing through a heavily industrialized area near the Port of Green Bay. I-43 ends at I-41/US 41/US 141. I-43's lowest traffic volume in this county is at the southernmost entry with a 2006 value of 22,100 vehicles per day near Denmark. Values around Green Bay range from 34,600 to 42,200 vehicles per day.
A multiple-vehicle collision on the northbound lanes of I-43 involving 52 vehicles, killing three and injuring at least 30 others, occurred on the Tower Drive Bridge at 6:45 a.m. March 12, 1990. The cause was a wall of fog with extremely limited visibility near the Fox River on an otherwise clear day.
On October 10, 2002, a multiple-vehicle collision occurred on I-43, just south of Cedar Grove. The accident occurred on southbound I-43 in Sheboygan County just north of the Ozaukee–Sheboygan county line. It involved 50 vehicles and was found to have been caused by low visibility due to fog at a point where the freeway comes its closest to paralleling Lake Michigan, 0.7 miles (1.1 km) from shore. The accident and resulting fires led to the deaths of 10 individuals making this accident the deadliest in Wisconsin history. In addition to the fatalities, 36 people were also injured in the pile-up. According to witnesses at the scene, fire from the wreckage rose over 20–30 feet (6.1–9.1 m) into the air. First responders said many of the bodies they recovered were burned beyond recognition. Then-Sheboygan County Sheriff Loni Koenig said of the accident site, "In my 21 years [of law enforcement], this is the most horrific scene I have ever seen, and I'm sure that it is for many of the people there." The accident has since been described as the worst traffic accident in Wisconsin state history.
Another multiple-vehicle collision occurred on March 5, 2019, on the Leo Frigo Bridge because of ice on the bridge. Nobody was severely injured.
I-43's interchange with I-39 and I-90 is currently undergoing expansion, which includes rebuilding the I-43 interchange at I-39/90 and WIS 81. I-43 will end at I-39/90 at a directional T-interchange, while WIS 81 will be extended to I-43's exit 2 by 2021.
|Rock||Beloit||0.00||0.00||1|| WIS 81 west (Milwaukee Road) – Beloit|
I-39 / I-90 – Chicago, Madison
|Signed as exits 1A (I-39 south/I-90 east) and 1B (I-39 north/I-90 west); roadway continues west as WIS 81 (Milwaukee Road); I-39/I-90 exit 185|
|Town of Turtle||1.43||2.30||2||CTH-X (Hart Road)|
|Town of Clinton||6.97||11.22||6||WIS 140 – Clinton, Avalon|
|Walworth||Town of Darien||14.99||24.12||15||US 14 – Janesville, Darien, Whitewater|
|17.92||28.84||17||CTH-X – Delavan, Darien|
|Town of Delavan||21.13||34.01||21||WIS 50 – Delavan, Lake Geneva|
|Elkhorn||25.81||41.54||25||WIS 67 – Elkhorn, Williams Bay|
|Town of Lafayette||27.45||44.18||27||US 12 – Madison, Lake Geneva||Signed as exits 27A (US 12 east) and 27B (US 12 west)|
|28.98||46.64||29||WIS 11 – Elkhorn, Burlington|
|34.04||54.78||33||CTH-D (Bowers Road) – Honey Creek|
|Town of East Troy||36.78||59.19||36||WIS 120 – East Troy, Lake Geneva|
|East Troy||38.54||62.02||38||WIS 20 – East Troy, Waterford|
|Waukesha||Mukwonago||43.84||70.55||43||WIS 83 – Waterford, Mukwonago||Southwestern end for Rock Freeway name, southern terminus of Alt I-43|
|Big Bend||50.71||81.61||50||WIS 164 (Big Bend Road) – Waukesha, Big Bend|
|New Berlin||54.11||87.08||54||CTH-Y (Racine Avenue) – Muskego||Southern terminus of Alt. I-43|
|57||CTH-O (Moorland Road)|
|58.88||94.76||59||To WIS 100 (Layton Avenue)||Northbound exit and southbound entrance|
|Milwaukee||Greenfield||60.92||98.04||60||US 45 south / WIS 100 (108th Street)||Southern end of US 45 concurrency; southbound exit and northbound entrance, northbound exit is via exit 59|
|61.09||98.31||61||I-41 north (Zoo Freeway) / I-894 west / US 41 north / US 45 north – Fond du Lac, Madison||Western end of I-41/I-894 concurrency; northern end of US 45 concurrency; signed as exit 4 southbound; concurrency uses I-894 exit numbers; northeastern end of Rock Freeway name; western end of Airport Freeway name; Hale Interchange|
|62.49||100.57||5||76th Street (CTH-U), 84th Street||Signed as exits 5A (South 76th Street) and 5B (South 84th Street)|
|62.78||101.03||5A||WIS 24 west (Forest Home Avenue)||Southbound exit and northbound entrance|
|64.51||103.82||8||WIS 36 (Loomis Road)|
|9||WIS 241 (27th Street)||Signed as exits 9A (WIS 241 south) and 9B (WIS 241 north) southbound|
|I-41 south (North–South Freeway) / I-94 east / US 41 south – Chicago, Mitchell Airport||Eastern end of I-41/I-894/US 41 concurrency; southern end of I-94 concurrency; signed as exits 10A (I-43 north/I-94 west) and 10B (I-41 south/I-94 east/US 41 south) northbound, and as no number (I-94 east/US 41 south) and exit 316 (I-43 south/I-894 west) westbound; concurrency uses I-94 exit numbers; eastern end of Airport Freeway name; southern end of North–South Freeway name; Mitchell Interchange|
|314||Holt Avenue, Howard Avenue||Signed as exits 314A (Holt Avenue) and 314B (Howard Avenue) southbound|
|312||Becher Street, Mitchell Street, Lapham Boulevard, Greenfield Avenue, Lincoln Avenue||Signed as exits 312A (Lapham Boulevard) and 312B (Becher Street) southbound|
|71.26||114.68||311||WIS 59 (National Avenue) / 6th Street|
|71.73||115.44||310C||I-794 (East–West Freeway) – Lakefront, Port of Milwaukee||Marquette Interchange; signed as exit 72B southbound; I-794 exit 1|
|71.86||115.65||310B||I-94 west (East–West Freeway) – Madison||Northern end of I-94 concurrency; Marquette Interchange; signed as exit 72D southbound|
|72.25||116.28||72A||Michigan Street, 10th Street||Northbound exit and southbound entrance|
|72.44||116.58||72C||Kilbourn Avenue||Northbound exit only|
|72.74||117.06||72E||US 18 (Highland Avenue, 11th Street)||Southbound exit and northbound entrance|
|72.91||117.34||73A||WIS 145 (Fond du Lac Avenue, McKinley Avenue)|
|75||Keefe Avenue, Atkinson Avenue|
|76||WIS 57 / WIS 190 (Capitol Drive, Green Bay Avenue)||No southbound exit to northbound WIS 57; signed as exits 76A (WIS 57/WIS 190 east) and 76B (WIS 57/WIS 190 west) northbound|
|Glendale||76.93||123.81||77||Hampton Avenue||Southbound exit and northbound entrance; signed as exits 77A (east) and 77B (west)|
|78||Silver Spring Drive, Port Washington Road|
|River Hills||80.13||128.96||80||CTH-PP (Good Hope Road)|
|Bayside||82.03||132.01||82||WIS 100 west / WIS 32 east / LMCT (Brown Deer Road)||Southern end of WIS 32 concurrency; signed as exits 82A (WIS 32 east) and 82B (WIS 100 west)|
|Ozaukee||Mequon||83.58||134.51||83||CTH-W (Port Washington Road)||Northbound exit and southbound entrance|
|85||WIS 57 south / WIS 167 west (Mequon Road)||Southern end of WIS 57 concurrency|
|Town of Grafton||89.33||143.76||89||CTH-C (Pioneer Road) – Cedarburg|
|Grafton||92.14||148.28||92||WIS 60 west (Washington Street) / CTH-Q east (Ulao Road) – Grafton, Cedarburg, Ulao|
|Town of Grafton||93.56–|
|93||WIS 32 north (Spring Street) / CTH-V south (Grafton Avenue) / LMCT – Grafton, Port Washington||Northern end of WIS 32 concurrency; northern end of North–South Freeway|
|Saukville||96.66||155.56||96||WIS 33 (Grand Avenue) – Saukville, Port Washington|
|Town of Saukville||97.54||156.98||97||WIS 57 north – Fredonia, Random Lake, Waldo, Plymouth||Northern end of WIS 57 concurrency; northbound exit and southbound entrance|
|Town of Port Washington||100.73||162.11||100||WIS 32 south (Wisconsin Street) / CTH-H west / LMCT – Fredonia, Port Washington||Southern end of WIS 32 concurrency; CTH-H is the former WIS 84|
|Town of Belgium||107.57||173.12||107||CTH-D – Belgium, Lake Church|
|Sheboygan||Town of Holland||112.82||181.57||113||WIS 32 north – Cedar Grove||Northern end of WIS 32 concurrency|
|116||CTH-AA (Foster Road) – Oostburg|
|Town of Wilson||120.36–|
|120||CTH-V / CTH-OK (South Business Drive) – Waldo, Sheboygan|
|Town of Sheboygan||123.31–|
|123||WIS 28 (Washington Avenue) / CTH-A / CTH-TA / LMCT – Sheboygan, Sheboygan Falls|
|Sheboygan||125.90||202.62||126||WIS 23 (Kohler Memorial Drive) – Sheboygan, Plymouth|
|Town of Sheboygan||128.60||206.96||128||WIS 42 (Calumet Drive) / LMCT – Sheboygan, Howards Grove|
|Town of Mosel||131.50||211.63||131||Rowe Road||Southbound entrance, northbound exit; unsigned event-only ramp for Whistling Straits|
|Manitowoc||Town of Centerville||137.57||221.40||137||CTH-XX – Kiel, Cleveland||CTH-XX is the former WIS 149|
|Town of Newton||144.17||232.02||144||CTH-C – St. Nazianz, Newton|
US 151 (Calumet Avenue) / WIS 42 south / Bus. WIS 42 / LMCT – Manitowoc, Fond du Lac
|Southern end of WIS 42 concurrency, Northern terminus of Alt I-43|
|151.72||244.17||152||US 10 east (Waldo Boulevard) / WIS 42 north / CTH-JJ – Manitowoc, Sturgeon Bay||Northern end of WIS 42 concurrency, southern end of US 10 concurrency, to Sturgeon Bay not signed southbound|
|Town of Manitowoc Rapids||154.75||249.05||154||US 10 west / WIS 310 – Appleton, Two Rivers||Northern end of US 10 concurrency|
|Town of Kossuth||157.80||253.95||157||CTH-V – Mishicot, Francis Creek|
|160.53||258.35||160||CTH-K – Kellnersville|
|Town of Cooperstown||164.24||264.32||164||WIS 147 / CTH-Z – Maribel, Mishicot, Two Rivers||Mishicot not signed southbound, Two Rivers not signed northbound|
|Brown||Denmark||170.83||274.92||171||WIS 96 / CTH-KB – Greenleaf, Denmark|
|Town of Ledgeview||177.99||286.45||178||US 141 (Main Street) / CTH-MM to WIS 29 – Bellevue, Kewaunee|
|Bellevue||180.49||290.47||180||WIS 172 west to I-41 / US 41 / WIS 32 – Austin Straubel International Airport||To I-41 not signed northbound while WIS 32 not signed southbound|
|181.71||292.43||181||CTH-JJ / Manitowoc Road|
|183||CTH-V / Mason Street|
|185||WIS 54 / WIS 57 / LMCT (University Avenue) – Sturgeon Bay, Algoma, Green Bay|
|187||Webster Avenue, East Shore Drive|
|Leo Frigo Memorial Bridge over the Fox River|
|192B||I-41 south / US 41 south to WIS 29 – Appleton||Northbound exit and southbound entrance; exit 170B on I-41; no access to US 141 south; northern terminus of I-41|
|192A||US 41 / US 141 north / LMCT – Marinette, Iron Mountain||Exit 170B on US 41|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
|Location||Manitowoc, Sheboygan, Ozaukee, Milwaukee, and Waukesha counties|
I-43 has an alternate route within Manitowoc, Sheboygan, Ozaukee and Milwaukee counties for situations requiring a road closure starting at WIS 83 at exit 43 in Mukwonago to Calumet Avenue (U.S. 151) at exit 149 in Manitowoc, mainly using the former US 141 and WIS 15 locally known as Port Washington Road and designated as CTH-W in Milwaukee and Ozaukee counties, while as a series of roads in Waukesha County. Past WIS 33 in Saukville, the divided limited-access WIS 57 at the I-43/WIS 57 split is designated Alt. I-43 to WIS 23 in Plymouth, where it diverts off WIS 32 at Sheboygan, then north to WIS 42 at Howards Grove north to Manitowoc.
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- Wisconsin Department of Transportation (2007). 2007 Interstate System Ozaukee County Annual Average Daily Traffic (PDF) (Map). Scale not given. Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on June 1, 2010. Retrieved March 7, 2008.
- Wisconsin Department of Transportation (2005). 2005 Sheboygan County Annual Average Daily Traffic (PDF) (Map). Scale not given. Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on July 6, 2008. Retrieved March 7, 2008.
- Wisconsin Department of Transportation. Manitowoc County (PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on April 13, 2007. Retrieved January 17, 2008.
- Wisconsin Department of Transportation (2005). "2005 Interstate System Manitowoc County Annual Average Daily Traffic" (PDF). Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on July 6, 2008. Retrieved March 7, 2008.
- Wisconsin Department of Transportation. Brown County (PDF) (Map). 1:100,000. Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on April 13, 2007. Retrieved January 17, 2008.
- Wisconsin Department of Transportation (2006). 2006 Interstate System Brown County Annual Average Daily Traffic (PDF) (Map). Scale not given. Madison: Wisconsin Department of Transportation. Archived from the original (PDF) on July 20, 2008. Retrieved March 7, 2008.
- "Lessons from 1990 Bridge Crash". Green Bay, WI: WLUK-TV. July 27, 2009. Archived from the original on January 30, 2010. Retrieved May 18, 2013.
- "Three Killed in Bridge Crash". Lawrence Journal-World. March 12, 1990. p. 2A. Retrieved May 18, 2013.
- Benson, Dan & Johnson, Mike (December 21, 2008). "Drivers Cite Poor Visibility, Slick Pavement in Pileup". Milwaukee Journal Sentinel. Retrieved June 4, 2011.
- "15 Hurt in 38-Vehicle Pileup". Iron Mountain Daily News. March 6, 2010. Archived from the original on July 20, 2011. Retrieved June 4, 2011.
- Wentz-Graff, Kristyna (October 11, 2002). "At Least 10 Killed in Multi-Car Crash in Wisconsin". USA Today. Associated Press. Retrieved June 4, 2011.
- Borowski, Greg J.; Benson, Dan & Hansen, Jessica (October 10, 2002). "10 die in horrific pileup". Milwaukee Journal Sentinel. Archived from the original on September 29, 2007. Retrieved May 13, 2007.
- Amundsen, Mackenzie (March 5, 2019). "30-vehicle pile-up on Leo Frigo Bridge started with one car hitting ice". Green Bay: WBAY-TV.
- Wisconsin Department of Transportation (n.d.). "I-39/90 Expansion Project: Illinois State Line to Madison, Dane and Rock Counties". Wisconsin Department of Transportation. Retrieved April 11, 2020.
- Wisconsin Department of Transportation. "North–South (Silver Spring Dr. to WIS 60), Glendale to Grafton—Milwaukee and Ozaukee Counties". Wisconsin Department of Transportation I-43. Retrieved April 11, 2020.
- Regional Logs:
- Wisconsin Department of Transportation (December 31, 2008). State Trunk Highway Log: Southwest Region. Madison, WI: Wisconsin Department of Transportation.
- Wisconsin Department of Transportation (December 31, 2008). State Trunk Highway Log: Southeast Region. Waukesha, WI: Wisconsin Department of Transportation.
- Wisconsin Department of Transportation (May 14, 2009). State Trunk Highway Log: Northeast Region. Green Bay, WI: Wisconsin Department of Transportation.
- King, Randy (August 16, 2010). "Exit Numbers on I-43". Madison, WI: Wisconsin Department of Transportation. Archived from the original on May 16, 2011. Retrieved March 21, 2011.
- Daykin, Tom (June 2, 2010). "Work To Begin on I-43 Interchange near Whistling Straits". Milwaukee Journal Sentinel. Archived from the original on June 6, 2010. Retrieved March 21, 2011.
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