U.S. Route 63 in Iowa

Spearheaded by former state representative J.B. McHose of Boone, the Daniel Boone Trail Association was created with the idea of creating the pre-eminent north–south highway in the country at the time. McHose met with chambers of commerce in cities along the proposed route in order to drum up interest. The route was intended to travel from St. Louis, Missouri, to St. Paul, Minnesota, by way of Ottumwa, Oskaloosa, Des Moines, Boone, Fort Dodge, Humboldt, and Algona.[17] Through southern Iowa, it was not immediately known where the trail would be located. Meetings in early 1916 clarified that the route between Des Moines and Oskaloosa would follow the northern bank of the Des Moines River and pass through Pella and Prairie City. An alternate route had been proposed through Knoxville and Albia south of the river.[18]

Before numbered highways and road maps became the norm for wayfinding, blue books were an important way for the traveling public to get from place to place. In 1916, then the president of the Daniel Boone Trail Association, McHose accompanied a pathfinder writing for a blue book from Boone to Ottumwa, ensuring the Daniel Boone Trail was recorded correctly for the next edition. At the same time, route markers were being placed along the route. The signs measured 10 by 30 inches (250 by 760 mm) and said "Daniel Boone trail, Canada to the gulf."[19]

In 1919, the Iowa General Assembly passed a bill that created a fund for improving and hard-surfacing nearly 6,300 miles (10,100 km) of primary roads in the state. The primary road system was to connect every city and town with at least 1000 inhabitants.[20] The bill gave Iowa's 99 counties the responsibility for maintaining the roads, which had previously fallen upon road associations that sponsored their respective highways.[21] The new primary roads were assigned route numbers, a trend seen in other Midwestern states. Route numbers were painted onto telegraph and telephone poles in order to guide travelers without the need for maps.[22] Because of the snaking route the Daniel Boone Trail took through the state, it was assigned multiple route numbers: Primary Road No. 13 from the Missouri state line to No. 24 near Hedrick, thence on No. 24 to Oskaloosa, No. 2 from Oskaloosa to Des Moines, No. 60 from Des Moines to Boone, No. 6 from Boone to Ogden, No. 90 from Ogden to Harcourt, and lastly No. 16 from Harcourt to the Minnesota state line.[7]

Iowa US 63 shield

In the mid-1920s, automobile associations continued to sponsor their named routes — there were 64 such named routes in Iowa — on top of the route numbers given by the state highway commission. This proved to be more confusing than helpful to the casual traveler, so in 1924, the American Association of State Highway Officials (AASHO, later AASHTO) called for a national system of interstate highways. Of the 75,884 miles (122,123 km) proposed by AASHO, nearly 3,000 miles (4,800 km) were allocated to Iowa.[8] Across the country, support for the system was nearly unanimous among state highway officials and the new national routings and route numbers were assigned in 1925. The Iowa State Highway Commission chose to renumber a few highways as to not have conflicting route numbers along important routes. U.S. Highway 63 was designated along Primary Roads No. 13, 24, and 2, which was the Daniel Boone Trail from Missouri to Des Moines.[6] Once the U.S. Highway System was established, the automobile association-sponsored roads gradually disappeared.[8]

A map of Iowa's U.S. Highways as laid out in 1926

The new US 63 entered Iowa near Bloomfield and traveled north through Ottumwa to Oskaloosa. There it turned to the northwest to go through Pella, Monroe, and Prairie City. The national northern end of the highway was at the corner of Grand Avenue and E. 14th Street near the Iowa State Capitol where US 32 and US 65 split.[23] When it was designated, only a small percentage of the route was paved – a short section south of Oskaloosa and all it in Polk County.[24] By August 1934, the whole route was paved.[25]

In 1933, residents of southeastern Minnesota expressed interest to the state highway department for an extension of US 63 from Iowa through Minnesota and to Lake Superior in Wisconsin.[26] Around the same, AASHO was conducting a review of the young U.S. Highway System. In other states, some U.S. Highways split into two routes, e.g. US 70N and US 70S; these splits were found to not be particularly useful for the traveling public and AASHO recommended their removal.[27]

At AASHO's annual meeting in 1934, among the topics discussed was the highway system itself. Attendees decreed that the system should serve interstate traffic and that shorter routes that do not serve that purpose should be consolidated into other highways or removed from the system entirely. Additionally, any new routes in the system would only be approved in areas that were unoccupied by any other routes.[28] At that same meeting, US 63 away from Des Moines and instead north from Oskaloosa over Iowa 59. This created a route from Turrell, Arkansas, to Ashland, Wisconsin, by way of Waterloo, Rochester, Minnesota, and Red Wing, Minnesota. Due to the major change in the route, the abandoned segment from Oskaloosa to Des Moines was renumbered U.S. Highway 163.[29] The newly numbered US 163 did not last long. In 1937, AASHO changed its policies with regards to numbered highways entirely within one state. As a result, Iowa 163 replaced US 163 in its entirety; US 161 in eastern Iowa was also affected.[30] When it became US 63, the former Iowa 59 was nearly fully paved. Only the portion of the route in Poweshiek County south of US 6 was a gravel road.[31] That section was paved in 1938.[32]

The Jefferson Street bridge while under construction in 1935

After two floods inundated Ottumwa in 1947, the city created an ambitious public works project that began in 1955. The main part of the project was the straightening and widening of the Des Moines River through the city. The main channel of the river was an oxbow that curved into the southern half of the city; a smaller channel bordered the northern half.[33] The smaller northern channel was to be widened to accommodate the full river. Dirt excavated for the new channel was to be used to build levees and to provide fill dirt for the relocation of US 63 and US 34.[34] US 63 entered Ottumwa from the south along Madison Street and met US 34 at the foot of the river. They then crossed on the Jefferson Street bridge; US 34 split away at the intersection with Main Street. US 63 continued north on Jefferson but turned west on Vanness Street for a block before turning north on Court Street and out of town.[35] The new routing of US 63 followed the bank of the Des Moines river more closely. It intersected US 34 near the John Deere plant and followed the new river bank. US 63 turned north onto the new Wapello Street viaduct, passed over downtown, and then north along a new four-lane road that connected to Court Street.[34] The $2-million viaduct was the last piece of the $22-million project (equivalent to $13.6 million and $149 million, respectively, in 2021 dollars[36]) that lasted ten years.[12]

In the late 1950s, an editorial published in the Waterloo Daily Courier called for the Iowa State Highway Commission to widen the highways in the Waterloo area. It cited a statistic that suggested a highway with over daily traffic of over 4000 vehicles should be expanded to four lanes. On US 63, the highway commission's count in 1956 found that 4430 vehicles north of Waterloo and 2490 vehicles south of the city used the highway daily. Traffic on US 63 had nearly doubled since the previous count in 1954.[37] Traffic entered Waterloo from the southwest on a winding road that became 4th Street. At Washington Street, which carried US 218, the highway split into a one-way couplet between Washington and Franklin streets. Northbound traffic used 5th Street and southbound traffic Park Avenue; both streets traveled over the Cedar River and passed through downtown Waterloo. At Franklin, which carried US 20, the two directions of US 63 and they followed Franklin for a few blocks before turning north onto Logan Avenue. At the intersection with Center Street, there was a level crossing with the Illinois Central Railroad.[38]

Two years later, the commission announced $8 million in highway projects (equivalent to $57.7 million in 2021 dollars[36]) in the Waterloo area, among which was relocating US 63 on the west side of Waterloo, a shifted Cedar River crossing, and a rail crossing north of downtown. In 1960, it was announced that the rerouted path of US 63 in western Waterloo would run adjacent to the Chicago Great Western railroad tracks that ran along Black Hawk Creek. It would then meet US 218 near the John Deere plant and then use Mullan Avenue and a new bridge at 1st Street across the Cedar River to US 20.[39] North of US 20, an underpass would be constructed to eliminate the Illinois Central crossing.[40] The new underpass opened with great fanfare on October 31, 1963, as it brought relief from a bottlenecks brought on by the nearby rail yard. A pedestrian bridge over US 63 was built as well.[41]

Parts of the western Waterloo route opened in 1962. It was opened up from Hudson to San Marnan Drive, which was Iowa 412. The rest of the western Waterloo highway was delayed by the city so the Army Corps of Engineers could complete a study on flood control in the downtown area. It was not known if the heights of any potential new levees would require a new Mullan Avenue bridge.[42] The new section of highway from Hudson featured a 90-degree turn, a temporary stopgap measure until the rest of the highway could be built to US 218. Inadequate signage notifying drivers of an abrupt speed limit change from 70 to 25 miles per hour (115 to 40 km/h) led to numerous accidents where drivers did not handle the turn correctly.[43] The connection to US 218 opened on December 16, 1968.[13]

A new bridge over the Cedar River opened in June 1968, but northbound US 63 traffic was not rerouted onto the new span right away. Traffic lights and street lights were not yet installed along the bridge and widened First Street.[44] Southbound US 63 was using the Mullan Avenue shortly after the First Street bridge opened. The Waterloo City Council voted in March 1969 to replace the Mullan Avenue bridge with a new span. The old bridge was built in 1913, but it was determined to be in worse condition than originally believed.[45] The Mullan Avenue bridge closed on February 16, 1970, and southbound US 63 traffic was detoured to 5th Street; by then northbound US 63 traffic had been using the First Street bridge.[46] A month later, while using a wrecking ball on one of the support arches, the rest of bridge collapsed into the Cedar River. A small tractor and large air compressor fell into the water with the bridge.[47] The new Mullan Avenue bridge opened on November 23, 1970.[48]

The 1980s and 1990s were a busy time for road construction in the Waterloo–Cedar Falls metro area. Waterloo mayor Leo P. Rooff in the 1970s declined extending I-380 to Cedar Falls by using the Federal Highway Administration's interstate substitution program; money that was earmarked for interstate highway construction could be used for other projects. Rooff wanted the money to be used for existing infrastructure, which was not in good condition. Some of the money saved was used to build the Iowa 58 expressway in Cedar Falls and the US 218 expressway connecting the two cities.[49] US 20 was rerouted onto a freeway south of Iowa 412 in 1983; the interchange between US 20 and US 63 was built overtop Iowa 412's western end. I-380 was completed in 1985 finally connecting the area to the Interstate Highway System.[50] A 4-cent-per-US-gallon (1.1 ¢/L) increase in Iowa's gas tax in 1988 (equivalent to 9 ¢/US gal [2.4 ¢/L] in 2021 dollars[51]) also added some much needed funds for highway construction.[52] In the early 1990s, connecting Waterloo to Rochester, Minnesota, was looked at as the next big project. A study suggested building a four-lane road in stages all the way into Minnesota, but also suggesting improving the existing two-lane roadway and constructing bypasses around cities.[53] Meanwhile, construction of a bypass around Denver was ongoing.[54] The Denver bypass was initially approved in 1986, but it was not programmed for construction until 1991–1992.[55][56] Traffic was routed onto the new bypass in October 1994, but the project wasn't completed for another month.[57]

In 1996, the Iowa Transportation Commission approved an ambitious, $1.7-billion highway construction plan (equivalent to $2.75 billion in 2021 dollars[36]) that would expand six important corridors to four-lane expressways—and not freeways—including the Des Moines to Burlington route, by 2004.[58] Local officials applauded the project, stating that it would improve the state's economy overall and help southeastern Iowa businesses locally.[59] The project received a major boost when President Bill Clinton signed a $216-billion highway bill on June 9, 1998, out of which $314 million was earmarked for Iowa projects (equivalent to $340 billion and $494 million in 2021 dollars, respectively[36]).[60] Plans to begin work on the new highway were submitted to the transportation commission and approved.[61]

Construction began on the Des Moines-to-Burlington route. Plans for US 63 between Oskaloosa and Ottumwa did not follow the routing of US 63. Instead, it was to follow Iowa 137 south out of Oskaloosa to Eddyville. Then it would follow Iowa 23 from Eddyville to near Chillicothe. From there it would curve east and rejoin US 63 near the Ottumwa Regional Airport.[62] Construction near Eddyville was halted temporarily when the palegreen orchid, a plant considered endangered in Iowa at the time, was found in the sand dune prairie near Eddyville.[63] The relocated highway opened on July 15, 1997.[64] At the same time, what was left of the former Iowa 23 from Ottumwa to Eddyville was turned over to Wapello County and the former routing of US 63 became a new Iowa 23 between Oskaloosa and Iowa 149 near Hedrick; that highway was extended from the new Iowa 23 south to the new expressway.[65]

Budget constraints in the early part of the 2000s caused the Iowa DOT to table some highway projects, but they were still committed to completing the six high-priority corridors.[66] Part of the budget issues were caused by a change in federal earmark philosophy. Prior to this change, the Congress would fund projects individually, but now funding was being given to states in the form of a block grant and discretion on how the funds would be used was now up to the states.[67] The DOT was able to achieve some savings by extending the timeline for completing the priority projects.[68] The Ottumwa bypass was one of the delayed roads. The Iowa Transportation Commission initially approved the road in 1998, but later put the project on hold.[69] The commission re-approved the plan for the nine-mile (14 km) road at a cost of $68 million (equivalent to $101 million in 2021 dollars[36]).[70]

Construction lasted for a couple years; crews were able to make use of a fruitful 2007 road construction season.[71] Ottumwa's bypass opened to traffic on November 19, 2007.[67][72] The new road shifted US 63 traffic out of downtown and onto US 34 heading east from the intersection of the two highways near the city's John Deere plant. The final section of the 165-mile-long (266 km) Des Moines to Burlington route was completed in November 2008. Governor Chet Culver presided over the ribbon cutting ceremony that celebrated the opening of the Fairfield bypass and the completion of the 1996 highway plan.[14] The next year, the Des Moines to Burlington route was given a single route number, Iowa 163, which had previously extended from Des Moines to Oskaloosa. Between Oskaloosa and Burlington, the Iowa 163 number was overlaid atop the existing route numbers, US 63 and US 34.[73]

Aerial view of New Hampton showing how US 63 bypasses the town

Plans for a bypass in New Hampton started in the early 1990s after a study reported that building a four-lane road that connected Waterloo and Rochester, Minnesota, was economically feasible.[53] The New Hampton city council discussed potential bypass routes as early as 1991.[74] Initial plans had included connecting the newly constructed bypass of Denver to the New Hampton bypass, but that section was shelved in 1995 due to budget cuts.[75] The actual design of the bypass was not approved until April 1998.[76] Later that year the Iowa DOT pledged to connect the Denver and New Hampton bypasses by 2001. Fourteen people died in accidents on the 15 miles (24 km) between the two cities from 1986 to 1994, so the announcement was welcomed by local residents.[77] In 2001, however, the section of US 63 between the cities found itself again removed from the DOT's five-year plan.[78]

The bypass of New Hampton was complete in 2002, but the four-lane connection to Denver was not. The transition from four lanes to two presented a few dangers – four-lane traffic must slow down from 65–70 to 55 mph (105–115 to 90 km/h) and then the two-lane road itself was in rough shape. Most frustrating to some was that the DOT already owned the right-of-way for the expanded highway, but they chose to allow farmers to grow oats on the land instead.[79] Road construction budgets received a major boost with the American Recovery and Reinvestment Act of 2009. Highway projects that had been pushed back, like the widening of US 63 between Denver and New Hampton, finally had a green light.[80]

Near Frederika, where the new highway bypassed two 90-degree curves, dirt fill was used from a nearby property that was slated for wetland restoration near the Wapsipinicon River. By using the nearby soil, an estimated $500 thousand was saved from the $2.82 million project (equivalent to $638,871 and $3.6 million in 2021 dollars, respectively[36]).[81] The expansion of US 63 from New Hampton to Iowa 188 was completed in 2009.[80] The rest of the connection to Denver was scheduled as part of $600 million in statewide road construction for 2012 (equivalent to $710 million in 2021 dollars[36]).[82]

The improvements through Waterloo that came about in the late 1960s were showing their age in the 2010s. The railroad underpass that was celebrated for reducing wait times was subject to flooding after a heavy rain. The four lanes of Logan Avenue were too narrow for turning traffic. The east side of Waterloo was seen as economically depressed. The local media saw an improved US 63 as a welcome mat to the downtown area and by extension, the east side. It was an opportunity to improve the way of life for everyone in Waterloo.[83] A tax increment financing district was created along Logan Avenue and through eastern Waterloo with the hope that the rebuilt highway would be a catalyst to economic growth.[84] Six houses were moved out of the construction zone along Logan Avenue and 24 other properties were torn down before work began.[85] These houses and businesses were removed to make room for walking trails along the highway; they were considered to be located too close to the highway.[15]

The project was divided into three phases: north of Newell Street, south of Franklin Street to Jefferson Street across the Cedar River, and the new viaduct between Franklin and Newell. Construction on the segment north of Newell began in 2013 and finished in 2016. The downtown phase was contracted out in January 2017 and finished in early 2019.[86][15] The biggest piece of the corridor improvement puzzle was the replacement of the railroad underpass. The DOT proposed going over the Canadian National rails instead of under.[87] The viaduct project was estimated to cost $26.4 million. The project entailed filling in the underpass, stabilizing the soil, and mitigating groundwater in addition to building the viaduct.[86] The completed road reopened on November 1, 2019; civic and business leaders held a small ceremony at the foot of the viaduct to celebrate its opening.[15]