160-768: Interstate 17 ( I-17 ) is a north–south Interstate Highway located entirely within the US state of Arizona . I-17's southern terminus lies in Phoenix , at I-10 / US 60 and its northern terminus is in Flagstaff , at Milton Road north of I-40 . Most of I-17 is known as the Arizona Veterans Highway . In the Phoenix metropolitan area, it is mostly known as the Black Canyon Freeway , however,
320-535: A concurrency or overlap. For example, I‑75 and I‑85 share the same roadway in Atlanta ; this 7.4-mile (11.9 km) section, called the Downtown Connector , is labeled both I‑75 and I‑85. Concurrencies between Interstate and US Highway numbers are also allowed in accordance with AASHTO policy, as long as the length of the concurrency is reasonable. In rare instances, two highway designations sharing
480-651: A 28-year-old brevet lieutenant colonel, accompanied the trip "through darkest America with truck and tank," as he later described it. Some roads in the West were a "succession of dust, ruts, pits, and holes." As the landmark 1916 law expired, new legislation was passed—the Federal Aid Highway Act of 1921 (Phipps Act). This new road construction initiative once again provided for federal matching funds for road construction and improvement, $ 75 million allocated annually. Moreover, this new legislation for
640-599: A bridge of I-17 from Mountain View Road to Metro Parkway, serving one station at Metro Parkway . I-17 ends at Milton Road ( SR 89A ) north of I-40 in Flagstaff . The I-17 corridor roughly follows the first stagecoach route through the Black Canyon, established in 1878 between Cañon (now Black Canyon City) and Prescott. A later highway through White Spar from Wickenburg to Yarnell was improved in 1925 and incorporated into US 89 in 1926. In 1936, SR 69
800-476: A change in the numbering system as a result of a new policy adopted in 1973. Previously, letter-suffixed numbers were used for long spurs off primary routes; for example, western I‑84 was I‑80N, as it went north from I‑80 . The new policy stated, "No new divided numbers (such as I-35W and I-35E , etc.) shall be adopted." The new policy also recommended that existing divided numbers be eliminated as quickly as possible; however, an I-35W and I-35E still exist in
960-535: A direct connection to 1500 West would improve safety and reduce congestion on mainline I-15 and US-89 by decreasing demand on Park Lane. The project is currently in design with plans for construction in 2024. Construction of the Shepard Lane interchange started in late February of 2024 In March 2022, the Utah Department of Transportation initiated an Environmental Impact Statement (EIS) for
1120-412: A distance of approximately seven miles (11 km). The project also replaced the existing pavement with new 40-year concrete, reconstructed the 14600 South ( SR-140 ) interchange as a single-point urban interchange to improve traffic flow, and installed new traffic management technology such as cameras, ramp meters, electronic message signs, and fiber optics. The project cost $ 215 million. With
1280-771: A general purpose lane from Utah SR-201 in Salt Lake City and South Salt Lake, affectionately known as "The Spaghetti Bowl", to 12300 South in Draper. In addition, the I-15/I-215 interchange in Midvale was modified, where traffic from westbound I-215 now enters directly onto I-15 prior to the 7200 South exit, instead of merging with I-215 eastbound traffic on the collector/distributor ramp then entering onto I-15 after 7200 South. The 7200 South on and off ramps were reconstructed to accommodate this modification. 7200 South
1440-584: A high-occupancy-vehicle (HOV) lane in both directions. In order to accommodate the new width of the freeway, bridges at Beck Street, US 89, and 1100 North were replaced. The bridges at 800 North and 1100 North were replaced by one bridge at 1100 North. A new single point interchange was constructed between 2008 and November 2010 at 11400 South in Draper . The project also widened I-15 from 10600 South to just past 11400 South from three to four general purpose lanes, extended
1600-511: A low mountain pass just after another ranch exit. The US 50 overlap then ends as I-15 passes through the northwestern corner of Scipio . Off the Scipio interchange, is an official rest stop courtesy of UDOT and Flying J . (US 50 eastbound serves as a connector to I-70 for southbound I-15 motorists.) Several miles north of Scipio, I-15 leaves Millard County and enters Juab County before turning northeastward again. After an interchange with
1760-404: A new Triumph Boulevard bridge over I-15, and bike and pedestrian improvements. The final cost for the project was $ 415 million. Future elements not being constructed at this time are expected to include a new North Lehi interchange, a one-way frontage road system extended from SR-92 to the new North Lehi interchange, and freeway-to-freeway connector ramps at 2100 North to connect I-15 to
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#17327942066501920-468: A new curb, gutter, and sidewalk. Construction was originally scheduled to begin in 2023 however, with the additional funding nearly doubling the size and effort necessary to design the improvements, construction will begin in 2025. The Utah Department of Transportation completed the Shepard Lane environmental assessment in July 2020. The study determined that a new interchange along with widening and providing
2080-513: A north-northeast course. After several miles, there is an interchange with Manderfield Road before I-15 winds through another mountain pass and reaches the Sulphurdale interchange. This mountain pass, with a summit located at milepost 124.8, is the highest point along I-15 in Utah, at 6,611 feet (2,015 m) above sea level. After passing west of the ghost town of Sulphurdale , it reaches
2240-469: A northbound offramp and a southbound onramp. After a slight jog to the east comes the junction with US 89 (500 West). This junction straddles the north–south border between West Bountiful and Bountiful. It is also a partial interchange in that it has only a southbound offramp and a northbound onramp. It also is the beginning of the second 1-15 / US 89 overlap. Continuing north, it leaves West Bountiful and enters Centerville before reaching
2400-539: A northbound offramp and a southbound onramp. Heading north-northeast, it reaches the I-15 ;/ Legacy Highway / US 89 / Park Lane ( SR-225 ) interchange. This sprawling interchange provides a northbound offramp and southbound onramp for US 89, a southbound offramp and a northbound onramp for Legacy Parkway, as well connection with Park Lane. The interchange is just west of the Lagoon amusement park and
2560-589: A numbering scheme in which primary Interstates are assigned one- or two-digit numbers, and shorter routes which branch off of longer ones are assigned three-digit numbers where the last two digits match the parent route. The Interstate Highway System is partially financed through the Highway Trust Fund , which itself is funded by a combination of a federal fuel tax and transfers from the Treasury's general fund. Though federal legislation initially banned
2720-491: A proposal for an interstate highway system, eventually resulting in the enactment of the Federal-Aid Highway Act of 1956 . Unlike the earlier United States Numbered Highway System, the interstates were designed to be all freeways, with nationally unified standards for construction and signage. While some older freeways were adopted into the system, most of the routes were completely new. In dense urban areas,
2880-559: A report called Toll Roads and Free Roads , "the first formal description of what became the Interstate Highway System" and, in 1944, the similarly themed Interregional Highways . The Interstate Highway System gained a champion in President Dwight D. Eisenhower, who was influenced by his experiences as a young Army officer crossing the country in the 1919 Motor Transport Corps convoy that drove in part on
3040-409: A single digit prefixed to the two-digit number of its parent Interstate Highway. Spur routes deviate from their parent and do not return; these are given an odd first digit. Circumferential and radial loop routes return to the parent, and are given an even first digit. Unlike primary Interstates, three-digit Interstates are signed as either east–west or north–south, depending on the general orientation of
3200-750: A speed limit of 45 mph (70 km/h) because it is a parkway that consists of only one lane per side of the highway. On the other hand, Interstates 15, 80, 84, and 215 in Utah have speed limits as high as 70 mph (115 km/h) within the Wasatch Front , Cedar City , and St. George areas, and I-25 in New Mexico within the Santa Fe and Las Vegas areas along with I-20 in Texas along Odessa and Midland and I-29 in North Dakota along
3360-460: A speed limit of 80 mph (130 km/h). Other Interstates in Idaho, Montana, Oklahoma, South Dakota and Wyoming also have the same high speed limits. In some areas, speed limits on Interstates can be significantly lower in areas where they traverse significantly hazardous areas. The maximum speed limit on I-90 is 50 mph (80 km/h) in downtown Cleveland because of two sharp curves with
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#17327942066503520-474: A suggested limit of 35 mph (55 km/h) in a heavily congested area; I-70 through Wheeling, West Virginia , has a maximum speed limit of 45 mph (70 km/h) through the Wheeling Tunnel and most of downtown Wheeling; and I-68 has a maximum speed limit of 40 mph (65 km/h) through Cumberland, Maryland , because of multiple hazards including sharp curves and narrow lanes through
3680-470: A total of four in each direction. Just after leaving Riverdale, the Interstate enters Ogden and reaches the 31st Street (3100 South / SR-79 ) interchange. Curving back to the northwest, the freeway comes to the 24th South ( SR-53 ) interchange. Although the signage specifies "24th Street", this partial interchange (which only provides a northbound offramp and a southbound onramp)
3840-403: Is actually with Pennsylvania Avenue (also SR-53), which promptly connects with 24th Street (2400 South) northeast of the interchange. As it leaves Ogden and enters West Haven , I-15 curves to the north-northwest before coming to the 21st Street (2100 South / SR-104 ) interchange. The freeway then leaves West Haven and enters Marriott-Slaterville and immediately crosses
4000-697: Is added before it crosses the Virgin River . This marks the lowest elevation along I-15 in Utah, 2,560 feet (780 m) above sea level. Immediately north of the Virgin River and partially spanning the Santa Clara River , is the Dixie Drive interchange. A collector ramp is added between Dixie Drive and the next interchange with Bluff Street ( SR-18 ). I-15 then narrows to two lanes in each direction and turns northeast again, where it passes
4160-543: Is also commonly believed the Interstate Highway System was built for the sole purpose of evacuating cities in the event of nuclear warfare . While military motivations were present, the primary motivations were civilian. The numbering scheme for the Interstate Highway System was developed in 1957 by the American Association of State Highway and Transportation Officials (AASHTO). The association's present numbering policy dates back to August 10, 1973. Within
4320-514: Is also a rest area for southbound traffic. At the north end of the airport, the freeway leaves Brigham City and, before continuing on a slightly more westerly, northern course. After about a mile (1.6 km) in unincorporated Box Elder County, I-15 enters Honeyville and then reaches the Honeyville ;/ Bear River (6900 North / SR-240 ) interchange. Continuing northwest, the Interstate leaves Honeyville and immediately crosses
4480-593: Is also the northern end of the I-15/I-84 overlap and the southern end of the I-15/SR-30 overlap. Straddling the northern city limits of Tremonton is another interchange signed as "Tremonton/Garland". This second interchange of the same name is with 1000 North. Curving slightly to the east, it passes by the western edge of Garland before coming to the Riverside (15200 North / SR-30) interchange, which
4640-426: Is also where the freeway leaves South Salt Lake enters Salt Lake City . After entering Salt Lake City, the Interstate jogs to the west for the next three interchanges. The first is with SR-269 and includes the offramps from northbound I-15/I-80 to eastbound 600 South and the onramps from westbound 500 South to southbound I-15/I-80. The next two interchanges are overlain and include I-80 (the northern end of
4800-627: Is an official rest stop courtesy of UDOT and Flying J. Curving northwest, it passes the eastern edge of the Provo Bay of Utah Lake before reaching Provo . Upon entering Provo, it intersects with South University Avenue (the southern terminus of US 189 ) and East Lakeview Parkway. The Interstate then continues northwest, bisecting the west side of Provo, with an interchange with Center Street ( SR-114 ) before leaving Provo and entering Orem . After an interchange with West University Parkway ( SR-265 ), immediately southwest of Utah Valley University ,
4960-423: Is in the preliminary stages of the design of a new interchange along I-15 at 1800 North. Additional funding was recently added to the project that will widen 1800 North from I-15 to 2000 West, providing improved mobility to residents of Sunset and Davis County at large. 1800 North will be reconstructed in concrete pavement and widened to include two lanes in each direction and a center turn lane, 12-foot shoulders, and
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5120-724: Is just east of that town. About a mile (1.6 km) north of the last interchange is the Utah–Idaho border, where I-15 leaves the Ogden–Clearfield metropolitan area. From there, I-15 continues north to Malad City and on to Pocatello . The southwest–north alignment followed by I-15 was a major transportation corridor in the early 20th century, followed by auto trails such as the Arrowhead Trail (south from Salt Lake City), Evergreen National Highway (entire length), and Banff–Grand Canyon Road (north from Nephi ). In 1926, when
5280-520: Is just southwest of that city and is the northern end of the I-15/SR-30 overlap. Continuing a slightly winding course north, the Interstate reaches the Plymouth (20800 North / SR-13 ) interchange, which is just northwest of that town. Heading north and then to the northeast, the freeway reaches the Portage (25800 North / Center Street), which is the last interchange in the state and
5440-492: Is on the southern border of Sandy , and is the first of three within that city. The next interchange is with 10600 South ( SR-151 ). The final interchange in Sandy is with 9000 South ( SR-209 ). Shortly after the last interchange in Sandy, it leaves that city and enters Midvale , with the only interchange in that city being with 7200 South ( SR-48 ). After leaving Midvale, I-15 enters Murray and immediately reaches
5600-405: Is only four lanes wide and is subject to frequent traffic jams on weekends as motorists travel to and from Sedona , Flagstaff , or other high country destinations. A third lane will be added in both directions between Anthem and Black Canyon City , but due to the mountainous topography north of Black Canyon City to Sunset Point, two flex lanes will be added in a separate carriageway next to
5760-552: Is the end of the second I-15 / US 89 overlap. From this interchange, it heads northwest before leaving Farmington and entering Kaysville . Just inside Kaysville are two former rest areas. While the ramps and parking areas are still intact, there are no signage or facilities remaining. Further on is the Kaysville (200 North / SR-273 ) interchange. Continuing northwest, I-15 leaves Kaysville and enters Layton , along with its three interchanges. The first interchange
5920-755: Is the state's only Metropolitan Statistical Area through which I-15 does not pass. In 1998, the Utah State Legislature designated Utah's entire portion of the road as the Veterans Memorial Highway . The Interstate passes through the fast-growing Dixie region, which includes St. George and Cedar City , and eventually most of the major cities and suburbs along the Wasatch Front, including Provo, Orem , Sandy , West Jordan , Salt Lake City, Layton , and Ogden . Around Cove Fort , I-70 begins its journey eastward across
6080-480: Is to have the highway route extend from Tamaulipas , Mexico to Ontario , Canada. The planned I-11 will then bridge the Interstate gap between Phoenix, Arizona and Las Vegas, Nevada , and thus form part of the CANAMEX Corridor (along with I-19 , and portions of I-10 and I-15 ) between Sonora , Mexico and Alberta , Canada. Political opposition from residents canceled many freeway projects around
6240-526: Is with 2100 North / 1200 West ( US 89 / SR-85 ). This also begins the first of two I-15 / US 89 overlaps. The final interchange in Lehi is with Timpanogos Highway / Clubhouse Drive ( SR-92 ), after which the Interstate gains an additional two lanes, which is just east of Thanksgiving Point . Past Lehi, the Interstate exits the Provo metropolitan area and Utah County to enter
6400-409: Is with 650 North, which also provides direct access to the west part of the airforce base. Just after this interchange, the freeway leaves Clearfield, turns north, and enters Sunset , but has no further interchanges before leaving that city and Davis County. Just prior to the next interchange, I-15 enters Weber County and the city of Roy . After curving slightly to the east, the freeway reaches
6560-453: Is with Layton Parkway and just north of it, the express lanes end, leaving just three lanes in each direction. The next two interchanges are with Hill Field Road ( SR-232 ) and then Antelope Drive (2000 North / SR-108 ). After leaving Layton, the Interstate enters Clearfield and reaches the 700 South ( SR-193 ) interchange. From this interchange, north I-15 runs along the western edge of Hill Air Force Base . The next interchange
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6720-615: The Bear River . It then enters the town of Elwood and reaches the Tremonton / Garland (5200 West / SR-13 ) interchange. The freeway then leaves Elwood and enters Tremonton shortly after that. Just inside Tremonton is the I-15/I-84/ SR-30 junction. From this junction, I-84 and SR-30 head northwest to Snowville and on to Burley and Boise , Idaho , while I-15 continues north through Tremonton. This interchange
6880-474: The Dallas–Fort Worth metroplex in Texas, and an I-35W and I-35E that run through Minneapolis and Saint Paul , Minnesota, still exist. Additionally, due to Congressional requirements, three sections of I-69 in southern Texas will be divided into I-69W , I-69E , and I-69C (for Central). AASHTO policy allows dual numbering to provide continuity between major control points. This is referred to as
7040-552: The Federal Aid Highway Act of 1956 into law. Under the act, the federal government would pay for 90 percent of the cost of construction of Interstate Highways. Each Interstate Highway was required to be a freeway with at least four lanes and no at-grade crossings. The publication in 1955 of the General Location of National System of Interstate Highways , informally known as the Yellow Book , mapped out what became
7200-630: The Grand Forks area have higher speed limits of 75 mph (120 km/h). As one of the components of the National Highway System , Interstate Highways improve the mobility of military troops to and from airports, seaports, rail terminals, and other military bases. Interstate Highways also connect to other roads that are a part of the Strategic Highway Network , a system of roads identified as critical to
7360-529: The Lincoln Highway , the first road across America. He recalled that, "The old convoy had started me thinking about good two-lane highways... the wisdom of broader ribbons across our land." Eisenhower also gained an appreciation of the Reichsautobahn system, the first "national" implementation of modern Germany's Autobahn network, as a necessary component of a national defense system while he
7520-680: The Salt Lake City metropolitan area as it passes through the Point of the Mountain . As the route enters the Salt Lake Valley from only one of three other points connecting Salt Lake County and Utah County (the others being SR-68 and Traverse Ridge Road), it turns northeast to pass by the eastern edge of Bluffdale . It then enters Draper and heads north to pass through the western part of that city, with four interchanges along
7680-506: The US Department of Defense . The system has also been used to facilitate evacuations in the face of hurricanes and other natural disasters. An option for maximizing traffic throughput on a highway is to reverse the flow of traffic on one side of a divider so that all lanes become outbound lanes. This procedure, known as contraflow lane reversal , has been employed several times for hurricane evacuations. After public outcry regarding
7840-470: The US Highways , which increase from east to west and north to south). This numbering system usually holds true even if the local direction of the route does not match the compass directions. Numbers divisible by five are intended to be major arteries among the primary routes, carrying traffic long distances. Primary north–south Interstates increase in number from I-5 between Canada and Mexico along
8000-557: The Wasatch Front , and the Provo–Orem metropolitan area . Turning northeast, it enters the town of Santaquin , where US 6 begins its overlap with I-15 at the interchange with East Main Street ;/ US 6 / SR-198 . Exiting Santaquin, the Interstate turns north to pass by the western edge of Spring Lake before entering Payson , turning northeast, and reaching the 800 South ( SR-178 ) interchange. Continuing northeast,
8160-538: The Wasatch Front , between Santaquin and Brigham City ) was raised to 80 mph (130 km/h). In 2015, the UDOT raised the speed limit on the Wasatch Front urban stretch through Salt Lake City to 70 mph (110 km/h). Also, in 2016, the speed limit through the St. George metro area was raised to 70 mph (110 km/h). As of October 2016, the longest continuous high-occupancy-vehicle (HOV) facility in
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#17327942066508320-525: The Weber River . The next interchange is with 12th Street (1200 South / SR-39 ), at which point the freeway loses one lane in each direction. Continuing on with three lanes in each direction, the Interstate reaches the 400 North interchange. Similar to the 24th Street interchange, although signage indicates "400 North", this interchanges actually connects with Pioneer Road, which promptly connects with 400 North just east of
8480-553: The West Coast to I‑95 between Canada and Miami, Florida along the East Coast . Major west–east arterial Interstates increase in number from I-10 between Santa Monica, California , and Jacksonville, Florida , to I-90 between Seattle, Washington , and Boston, Massachusetts , with two exceptions. There are no I-50 and I-60, as routes with those numbers would likely pass through states that currently have US Highways with
8640-527: The Willard Bay of the Great Salt Lake . Its next interchange is with 750 North / SR-315 . Straddling the northern border between Willard and Perry are ports of entry for both directions of traffic. Continuing north through Perry, it passes a rest area for northbound traffic before it reaches the next interchange, which is with 1100 South ( US 91 ). This interchange straddles
8800-480: The freeway status.) At the Durango Curve southwest of downtown, between the 19th Avenue and Buckeye Road interchanges, it picks up the designation Maricopa Freeway all the way to the southern terminus at the second I-10 junction. It is one of the metropolitan area's primary freeways . It has two interchanges with I-10 in Phoenix. The northwestern portion of Valley Metro 's light rail line runs over
8960-889: The 20th century, the United States Congress began funding roadways through the Federal Aid Road Act of 1916 , and started an effort to construct a national road grid with the passage of the Federal Aid Highway Act of 1921 . In 1926, the United States Numbered Highway System was established, creating the first national road numbering system for cross-country travel. The roads were state-funded and maintained, and there were few national standards for road design. United States Numbered Highways ranged from two-lane country roads to multi-lane freeways. After Dwight D. Eisenhower became president in 1953, his administration developed
9120-491: The 2600 South ( SR-93 ) interchange, which is centered on the border of North Salt Lake and Woods Cross . Continuing north once again, the Interstate reaches its next interchange, which is with 500 South ( SR-68 ). Parts of this interchange are spread over three cities, with Woods Cross on the south, a panhandle of Bountiful in the middle, and West Bountiful on the north. Continuing north, it comes to another partial interchange with 400 North, which only includes
9280-526: The 5600 South ( SR-97 ) interchange, which provides access to the north end of the airforce base, including the Hill Aerospace Museum that is located immediately north of the base. The next interchange is with Riverdale Road ( SR-26 ). As a partial interchange, there is only a northbound offramp to eastbound SR-26 and a southbound onramp from westbound SR-26. (Eastbound SR-26 provides the only access to eastbound I-84 .) At this interchange,
9440-504: The Black Canyon Freeway was built in 1950 west of downtown Phoenix and was extended to Grand Avenue in 1957. The freeway was extended to McDowell Road by 1971 and out of the Phoenix suburbs by 1974, at a cost of $ 33 million. By 1971, I-17 had been completed from Phoenix northward to Camp Verde where a short stretch had not been completed to standards. The stretch from SR 279 (now SR 260 ) north to SR 179
9600-619: The Cedar City I-15 Business Loop. Just north is the 200 South ( SR-56 ) interchange, which provides access to downtown Cedar City as well as the Cedar City Regional Airport . After this interchange, the freeway turns northeast before the final Cedar City interchange with SR-130 (once again). This interchange is also the northern end of the Cedar City I-15 Business Loop, although no longer indicated as such by signage. The freeway then passes by
9760-576: The Congress Hotel in Chicago. In the plan, Mehren proposed a 50,000-mile (80,000 km) system, consisting of five east–west routes and 10 north–south routes. The system would include two percent of all roads and would pass through every state at a cost of $ 25,000 per mile ($ 16,000/km), providing commercial as well as military transport benefits. In 1919, the US Army sent an expedition across
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#17327942066509920-527: The I-15 Business Loop and SR-160 —the city streets are South Main Street on the south and 1400 North on the north. Off the 1400 North interchange, there is an official rest stop, courtesy of Utah Department of Transportation (UDOT) and the local Texaco Station . The freeway then heads slightly westward until it passes by the western side of the community of Manderfield and curves back to
10080-530: The I-15 bridges at Church Street and 200 South were replaced and widened, an auxiliary lane was added from Layton Parkway to Hill Field Road, bridges at Gentile Street, 700 South, Union Pacific Railroad bridge, and 5600 South were widened and the bridge decks were replaced, the bridge at 650 North was widened, and new ramp metering was installed at the on ramps of Antelope Drive, 700 South, 650 North, and Riverdale Road. Express Lane tolling began along this corridor on October 31, 2022. The I-15 Southbound Project added
10240-482: The I-15 reconstruction project was the Utah Department of Transportation's first major Interstate reconstruction project. The project involved the renovation of 16.2 miles (26.1 km) of I-15 from 600 North in Salt Lake City to 10600 South ( SR-151 ) in Sandy . Improvements included repaving concrete, adding another general-purpose lane and a high-occupancy-vehicle (HOV) lane, along with an auxiliary lane between major interchanges in each direction through
10400-412: The I-80 overlap) and 400 South (West University Boulevard). (The later interchange only permits HOV or toll use of the northbound offramp and the southbound onramp from and to the respective express lanes of I-15/I-80.) North of the ramps with I-80, I-15 loses one lane, leaving three lanes, plus the express lane, in both directions. The next interchange is with 600 North ( SR-268 ), following which
10560-427: The Interstate 15 (I-15) Farmington to Salt Lake City Project. A 2019-2050 Regional Transportation Plan includes two projects that identify improvements to I-15 in Davis and Salt Lake Counties: • I-15 widening (from 5 lanes to 6 lanes in each direction) from Farmington to Salt Lake County line • I-15 widening (from 4 and 5 lanes to 6 lanes in each direction) in Davis County to 600 North The purpose of this EIS project
10720-407: The Interstate Highway System. Assisting in the planning was Charles Erwin Wilson , who was still head of General Motors when President Eisenhower selected him as Secretary of Defense in January 1953. Some sections of highways that became part of the Interstate Highway System actually began construction earlier. Three states have claimed the title of first Interstate Highway. Missouri claims that
10880-424: The Interstate Highway program. The Interstates of Alaska and Puerto Rico are numbered sequentially in order of funding without regard to the rules on odd and even numbers. They also carry the prefixes A and PR , respectively. However, these highways are signed according to their local designations, not their Interstate Highway numbers. Furthermore, these routes were neither planned according to nor constructed to
11040-445: The Interstate also transitions from Roy to Riverdale . Heading northwest, I-15 then merges with I-84, but there is no northbound access to I-84 nor westbound access from I-84 to I-15. This also begins the I-15/I-84 overlap. Immediately northwest of this interchange is the Ogden-Hinckley Airport ; however, since the airport is slightly above hill, it is not visible from the freeway. Two additional lanes are added north of this junction for
11200-452: The Interstate in the Salt Lake County region. This reconstruction cost $ 1.63 billion, with $ 448 million being federally funded and $ 1,184 million being funded by Utah . The I-15 EXPRESSLink project took place between December 2008 and fall 2010. It involved the renovation of I-15 between 500 North in Salt Lake City and the northern terminus of I-215 in North Salt Lake . Renovations included new concrete and added
11360-467: The Interstate reaches the Spaghetti Bowl , which is an interchange with I-80 and SR-201 (21st South Freeway). The southern overlap of I-80 begins at this point as well as the collector roads. The collectors, but not the main I-15 travel lanes, have interchanges with 2100 South and 1300 South, as well as West Temple Street ( SR-270 ) for northbound traffic only. (The West Temple Street offramps are signed as 900 South.) The Spaghetti Bowl
11520-542: The Parish Lane (400 North / SR-105 ) interchange. About a mile (1.6 km) north, I-15 begins a stretch where the Legacy Parkway (SR-67) parallels the Interstate on the west, with little more than train tracks in between. About another mile (1.6 km) north, the freeway leaves Centerville and enters Farmington . Next comes the partial interchange with 200 West ( SR-227 ), which only includes
11680-413: The Salt Lake City metropolitan area. Approximately 130 bridges were either constructed or reconstructed, including the conversion of seven diamond interchanges into single point urban interchanges , and the reconstruction of three major junctions with other Interstate and state routes, including I-80 , SR-201 , and I-215 . In addition, a traffic management system was added to the entire length of
11840-480: The U.S. is on I-15 in Utah , extending approximately 72.0 miles (115.9 km) from Spanish Fork to Layton with a single HOV lane each direction for a total of 144.0 miles (231.7 km) of HOV lanes. As of October 2022, an additional 10 miles in each direction was added extending the lanes from Spanish Fork to Riverdale for a total of 164 miles of HOV lanes. Taking place between April 1997 and July 2001,
12000-476: The U.S. state of Utah through the southwestern and central portions of the state, passing through most of the state's population centers, including St. George and those comprising the Wasatch Front : Provo–Orem , Salt Lake City , and Ogden–Clearfield . It is Utah's primary and only north–south interstate highway, as the vast majority of the state's population lives along its corridor; the Logan metropolitan area
12160-806: The US to determine the difficulties that military vehicles would have on a cross-country trip. Leaving from the Ellipse near the White House on July 7, the Motor Transport Corps convoy needed 62 days to drive 3,200 miles (5,100 km) on the Lincoln Highway to the Presidio of San Francisco along the Golden Gate . The convoy suffered many setbacks and problems on the route, such as poor-quality bridges, broken crankshafts, and engines clogged with desert sand. Dwight Eisenhower , then
12320-778: The United States, including: In addition to cancellations, removals of freeways are planned: The American Association of State Highway and Transportation Officials (AASHTO) has defined a set of standards that all new Interstates must meet unless a waiver from the Federal Highway Administration (FHWA) is obtained. One almost absolute standard is the controlled access nature of the roads. With few exceptions , traffic lights (and cross traffic in general) are limited to toll booths and ramp meters (metered flow control for lane merging during rush hour ). Being freeways , Interstate Highways usually have
12480-422: The United States. The project was completed on December 15, 2012—35 months from the original notice to proceed—and finished $ 260 million under budget (coming in at $ 1.465 billion total). I-15 CORE widened the freeway by two lanes in each direction and replaced the original asphalt with new 40-year concrete pavement; rebuilt 63 bridges; reconstructed 10 freeway interchanges; and extended
12640-499: The Yuba Lake Road is another interchange at Mills Junction / SR-78 just southeast of Chicken Creek Reservoir. The freeway then continues roughly north-northeast until it turns northeast to pass through the southern part of Nephi and an interchange with South Main Street ( SR-28 ). The freeway then turns north to pass through the eastern side of Nephi, with an interchange with 100 North ( SR-132 ). It then curves to
12800-481: The act was signed, and paving started September 26, 1956. The state marked its portion of I-70 as the first project in the United States completed under the provisions of the new Federal-Aid Highway Act of 1956. The Pennsylvania Turnpike could also be considered one of the first Interstate Highways, and is nicknamed "Grandfather of the Interstate System". On October 1, 1940, 162 miles (261 km) of
12960-684: The cancellation of the Somerset Freeway . This situation was remedied when the construction of the Pennsylvania Turnpike/Interstate 95 Interchange Project started in 2010 and partially opened on September 22, 2018, which was already enough to fill the gap. However, I-70 remains discontinuous in Pennsylvania , because of the lack of a direct interchange with the Pennsylvania Turnpike at
13120-406: The choice of routing destroyed many well-established neighborhoods, often intentionally as part of a program of " urban renewal ". In the two decades following the 1956 Highway Act, the construction of the freeways displaced one million people, and as a result of the many freeway revolts during this era, several planned Interstates were abandoned or re-routed to avoid urban cores. Construction of
13280-589: The city of North Salt Lake , and the Ogden–Clearfield metropolitan area , I-15 has the southbound on- and offramps for the Beck Street (US 89) interchange. Next is the junction between I-15 and I-215 (Belt Route), which only provides a southbound offramp from I-15 to I-215 and a northbound onramp from I-215 to I-15. Just after this is another partial interchange that only includes a southbound offramp to West Center Street. The freeway then heads northwest to
13440-664: The city. In some locations, low speed limits are the result of lawsuits and resident demands; after holding up the completion of I-35E in St. Paul, Minnesota , for nearly 30 years in the courts, residents along the stretch of the freeway from the southern city limit to downtown successfully lobbied for a 45 mph (70 km/h) speed limit in addition to a prohibition on any vehicle weighing more than 9,000 pounds (4,100 kg) gross vehicle weight . I-93 in Franconia Notch State Park in northern New Hampshire has
13600-401: The collection of tolls, some Interstate routes are toll roads , either because they were grandfathered into the system or because subsequent legislation has allowed for tolling of Interstates in some cases. As of 2022 , about one quarter of all vehicle miles driven in the country used the Interstate Highway System, which has a total length of 48,890 miles (78,680 km). In 2022 and 2023,
13760-489: The completion of The Point project, nearly all of I-15 along the Wasatch Front has been reconstructed within the past two decades. One last section in Lehi, from SR-92 to Main Street ( SR-73 ) remained and was widened spring 2018. The Utah Department of Transportation reconstructed the I-15 Technology Corridor between Lehi Main Street and SR-92 (Timpanogos Highway) starting in 2018. The Tech Corridor
13920-507: The construction and improvement of highways. The nation's revenue needs associated with World War I prevented any significant implementation of this policy, which expired in 1921. In December 1918, E. J. Mehren, a civil engineer and the editor of Engineering News-Record , presented his "A Suggested National Highway Policy and Plan" during a gathering of the State Highway Officials and Highway Industries Association at
14080-407: The contiguous United States, primary Interstates—also called main line Interstates or two-digit Interstates—are assigned numbers less than 100. While numerous exceptions do exist, there is a general scheme for numbering Interstates. Primary Interstates are assigned one- or two-digit numbers, while shorter routes (such as spurs, loops, and short connecting roads) are assigned three-digit numbers where
14240-507: The country. The Interstate merges with I-80 for about 3 miles (4.8 km) from South Salt Lake to just west of Downtown Salt Lake City and merges with I-84 from Ogden to Tremonton . Along nearly its entire length through the state, I-15 winds its way along the western edge of a nearly continuous range of mountains (including the Wasatch Range in the northern half of the state). The only exceptions are when it passes through
14400-623: The discontinuity, but they have been blocked by local opposition, fearing a loss of business. The Interstate Highway System has been expanded numerous times. The expansions have both created new designations and extended existing designations. For example, I-49 , added to the system in the 1980s as a freeway in Louisiana , was designated as an expansion corridor, and FHWA approved the expanded route north from Lafayette, Louisiana , to Kansas City, Missouri . The freeway exists today as separate completed segments, with segments under construction or in
14560-448: The dissemination of public information. As a result, the 2005 evacuation of New Orleans, Louisiana, prior to Hurricane Katrina ran much more smoothly. According to urban legend , early regulations required that one out of every five miles of the Interstate Highway System must be built straight and flat, so as to be usable by aircraft during times of war. There is no evidence of this rule being included in any Interstate legislation. It
14720-495: The east of side of Ash Creek Reservoir and then by the northwest corner of Zion National Park , with an interchange providing access to the Kolob Canyon area of the park. Next is an interchange that provides access to New Harmony (several miles west) and Kanarraville (several miles to the northeast). This interchange is also at the border of Washington County and Iron County . Just after entering Iron County, I-15 reaches
14880-464: The eastern edge of Enoch , but without an interchange within that city. After an interchange within the area of Summit , I-15 heads east-northeast before passing by the northwest edge of Parowan , with interchanges on the west (200 South / SR-143 ) and north (Main Street / SR-274 ) sides of town. After Parowan, the freeway curves back to a northeast course as it passes about a mile (1.6 km) west of Paragonah and reaches an interchange on
15040-496: The eastern end of the concurrency near Breezewood . Traveling in either direction, I-70 traffic must exit the freeway and use a short stretch of US 30 (which includes a number of roadside services) to rejoin I-70. The interchange was not originally built because of a legacy federal funding rule, since relaxed, which restricted the use of federal funds to improve roads financed with tolls. Solutions have been proposed to eliminate
15200-470: The eastern side of downtown St. George , with an interchange at St. George Boulevard ( SR-34 ). The Bluff Street and St. George Boulevard interchanges are the southern and northern ends of the St. George I-15 Business Loop . From this point north, I-15 generally follows the route of the Old US ;91 , maintaining a two-lane configuration until it reaches the Wasatch Front in the north-central part of
15360-450: The economy. Not just as a public works measure, but for future growth. Clay's committee proposed a 10-year, $ 100 billion program ($ 1.13 trillion in 2023), which would build 40,000 miles (64,000 km) of divided highways linking all American cities with a population of greater than 50,000. Eisenhower initially preferred a system consisting of toll roads , but Clay convinced Eisenhower that toll roads were not feasible outside of
15520-521: The existing southbound lanes. The lanes would be allocated depending on peak traffic direction. Gates or a similar mechanism would control access to these lanes. Construction began in 2022 and is scheduled to be completed in 2025. State Business Route 17 (also known as SR 17 Bus. ) was a former three-mile (4.8 km) business loop of I-17 that served the west side of Black Canyon City , Arizona . SR 17 Bus. followed Old Black Canyon Highway (formerly SR 69 before I-17 replaced most of
15680-492: The existing, largely non-freeway, United States Numbered Highways system. By the late 1930s, planning had expanded to a system of new superhighways. In 1938, President Franklin D. Roosevelt gave Thomas MacDonald , chief at the Bureau of Public Roads, a hand-drawn map of the United States marked with eight superhighway corridors for study. In 1939, Bureau of Public Roads Division of Information chief Herbert S. Fairbank wrote
15840-426: The federal government, Interstate Highways are owned by the state in which they were built. With few exceptions , all Interstates must meet specific standards , such as having controlled access, physical barriers or median strips between lanes of oncoming traffic, breakdown lanes , avoiding at-grade intersections , no traffic lights , and complying with federal traffic sign specifications. Interstate Highways use
16000-519: The final county ( Box Elder ) along its route in Utah, I-15 also enters the area of South Willard and then reaches the Willard (2000 West / SR-126 ) interchange. (SR-126 connects with US 89 just west of the interchange.) Before leaving the South Willard area and entering the city of Willard , I-15 begins about a two-mile (3.2 km) stretch that runs along the western shore of
16160-528: The first northbound exit and last southbound exit on I-15 in Utah. Heading north-northeast, it continues with two lanes in each direction until it reaches an interchange with Southern Parkway ( SR-7 ), which provides access to the St. George Regional Airport . After SR-7, the route turns north as it passes the Bloomington area of the City of St. George and an interchange at Brigham Road, where an auxiliary lane
16320-467: The first three contracts under the new program were signed in Missouri on August 2, 1956. The first contract signed was for upgrading a section of US Route 66 to what is now designated Interstate 44 . On August 13, 1956, work began on US 40 (now I-70) in St. Charles County. Kansas claims that it was the first to start paving after the act was signed. Preliminary construction had taken place before
16480-614: The first time sought to target these funds to the construction of a national road grid of interconnected "primary highways", setting up cooperation among the various state highway planning boards. The Bureau of Public Roads asked the Army to provide a list of roads that it considered necessary for national defense. In 1922, General John J. Pershing , former head of the American Expeditionary Force in Europe during
16640-637: The first wildlife overpass built in the United States. Before 1977 the route of I-15 (and US 91 before) was also designated SR-1 by the state of Utah, but no portion of the route was signed with this number. The last section of I-15 within the state of Utah (as well as the entire length of the route) was finally completed in November ;1990, only to have major reconstruction projects commence (starting in Salt Lake County) about 7 years later. The entire length of I-15 within Utah
16800-415: The freeway enters American Fork with interchanges at 500 East ( SR-180 ) on the south end of town and West Main Street / Pioneer Crossing ( SR-145 ) on the west end of town. After American Fork, the freeway enters Lehi with its first interchange at East Main Street ( SR-73 ). At this point, the Interstate narrows to three lanes (plus an express lane) in each direction. The next interchange in Lehi
16960-493: The freeway heads north along the western side of Orem. After interchanges with Center Street, and then 800 North ( SR-52 ), the Interstate curves northwest and immediately reaches the interchange with SR-241 (1600 North / 600 South). This interchange on the border of Orem and Lindon . Continuing northwest, I-15 passes through the western side of Lindon before passing by the southwest edge of Pleasant Grove , with an interchange at Pleasant Grove Boulevard. Next,
17120-511: The freeway jogs to the west for the next two interchanges. After the 900 West interchange (which does not include a northbound offramp) is the Warm Springs Road (northbound) and 2300 North (southbound) interchange. The freeway then returns to is northern course, but before leaving Salt Lake City and Salt Lake County, it has northbound on- and offramps for the Beck Street (US 89) interchange. After entering Davis County ,
17280-509: The freeway reaches the interchange with North Main Street ( SR-115 / 3200 West) in north Payson. Maintaining its course to the northeast, it passes the eastern edge of Benjamin , with an interchange with SR-164 (8000 South), and enters Spanish Fork and gains one lane in each direction. On the north side of Spanish Fork is an interchange with North Main Street (US 6 and SR-156 ), after which I-15 turns north and gains one more lane in each direction. This interchange also marks
17440-494: The freeway replaced between Phoenix and Cordes Junction. SR 69's mileposting was such that it coincided with US 89 's mileposting, which was 201.6 where the two routes intersected. When I-17 was constructed, the existing mileposting for SR 69 was retained. Due to increasing weekend traffic on I-17 between the Phoenix area and northern Arizona , ADOT plans to widen a 34-mile (55 km) section of freeway between Anthem and Sunset Point Rest Area. The current span
17600-903: The future Mountain View Corridor freeway . The Utah Department of Transportation extended the I-15 HOV/Toll Express Lanes from the Layton Parkway interchange to the Riverdale Road interchange. Construction began in May 2019 and was completed in October 2022. An HOV/Toll lane was added to both the northbound and southbound directions along the 10-mile (16 km) corridor to accommodate the growing population and traffic in northern Davis County and southern Weber County. The project included additional improvements;
17760-510: The high-occupancy-vehicle (HOV) lane that previously ended at 10600 South, and added an auxiliary lane between the two interchanges. The I-15 Corridor Expansion (CORE) project was a design–build project that reconstructed 24 miles (39 km) of I-15 in Utah County, Utah between Lehi Main Street to 8000 South Spanish Fork . The $ 1.725 billion project was the fastest billion-dollar public highway project ever completed in
17920-759: The high-occupancy-vehicle (HOV) lanes from Orem to Spanish Fork . (Prior to I-15 CORE, HOV lanes had already been installed from Lehi to Orem .) The South Davis Improvements project, which took place between April 2014 and August 2015, constructed new high-occupancy-vehicle (HOV) lanes between the I-215 interchange in North Salt Lake and the US ;89 interchange in Farmington ; replaced I-15 bridges at 2600 South, 1500 South, 500 South ( SR-68 ), and 400 North ( SR-106 ); reconfigured
18080-556: The highest speed limits in a given area. Speed limits are determined by individual states. From 1975 to 1986, the maximum speed limit on any highway in the United States was 55 miles per hour (90 km/h), in accordance with federal law. Typically, lower limits are established in Northeastern and coastal states, while higher speed limits are established in inland states west of the Mississippi River . For example,
18240-553: The highly populated coastal regions. In February 1955, Eisenhower forwarded Clay's proposal to Congress. The bill quickly won approval in the Senate, but House Democrats objected to the use of public bonds as the means to finance construction. Eisenhower and the House Democrats agreed to instead finance the system through the Highway Trust Fund , which itself would be funded by a gasoline tax. In June 1956, Eisenhower signed
18400-617: The highway now designated I‑70 and I‑76 opened between Irwin and Carlisle . The Commonwealth of Pennsylvania refers to the turnpike as the Granddaddy of the Pikes, a reference to turnpikes . Milestones in the construction of the Interstate Highway System include: The initial cost estimate for the system was $ 25 billion over 12 years; it ended up costing $ 114 billion (equivalent to $ 425 billion in 2006 or $ 618 billion in 2023 ) and took 35 years. The system
18560-459: The inefficiency of evacuating from southern Louisiana prior to Hurricane Georges ' landfall in September 1998, government officials looked towards contraflow to improve evacuation times. In Savannah, Georgia , and Charleston, South Carolina , in 1999, lanes of I-16 and I-26 were used in a contraflow configuration in anticipation of Hurricane Floyd with mixed results. In 2004, contraflow
18720-443: The interchange at 2600 South into a partial and 500 South into a full diverging diamond interchange ; and added active transportation improvements, with better pedestrian and bicycle facilities at 500 South, 400 North, and Parrish Lane. The entire project costed $ 126 million. The two-year Point Project widened I-15 from four to six lanes in each direction between 12300 South in Draper and SR-92 in Lehi,
18880-608: The interchange with the western end of I-70 . This interchange is on the border of Beaver and Millard counties. North of the I-15/I-70 interchange, I-70 heads east to Richfield and then toward Denver, Colorado , while I-15 continues north to pass by Cove Fort on the east and reach the Cove Fort ( SR-161 /Black Rock Road) interchange. Off the Black Rock Road interchange is an official rest stop, courtesy of UDOT and
19040-419: The interchange. North of this interchange, I-15 heads directly north to leave Marriott-Slaterville and enter Farr West . Continuing north, it reaches the 2700 North ( SR-134 ) before it curves to the north-northwest and leaves Farr West and Weber County. At the 2700 North interchange, the freeway narrows to two lanes in each direction and remains so for the remainder of its route in Utah. Upon entering
19200-562: The junction with I-215 , a beltway running through many of Salt Lake City's suburbs. Past this interchange, there are two more interchanges in Murray. The first is at 5400 South ( SR-173 ) and the second is with 4500 South / Taylorsville Expressway ( SR-266 ). After this interchange, the freeway leaves Murray and passes through the western end of Millcreek (an unincorporated suburb of Salt Lake City) before entering South Salt Lake . After an interchange with 3300 South ( SR-171 ),
19360-431: The last two digits match the parent route (thus, I-294 is a loop that connects at both ends to I-94 , while I-787 is a short spur route attached to I-87 ). In the numbering scheme for the primary routes, east–west highways are assigned even numbers and north–south highways are assigned odd numbers. Odd route numbers increase from west to east, and even-numbered routes increase from south to north (to avoid confusion with
19520-402: The local Chevron Station . I-15 meanders to the north-northeast before straightening out to the northeast–southwest of Kanosh . The freeway passes by the northwestern side of Meadow , having an interchange with North Main Street ( SR-133 ). It then passes through the western side of Fillmore . SR-99 follows the length of the I-15 Business Loop through Fillmore, connecting at 850 South on
19680-454: The mainline. Some auxiliary highways do not follow these guidelines, however. The Interstate Highway System also extends to Alaska , Hawaii , and Puerto Rico , even though they have no direct land connections to any other states or territories. However, their residents still pay federal fuel and tire taxes. The Interstates in Hawaii, all located on the most populous island of Oahu , carry
19840-548: The many mountains and valleys in northern Arizona. I-17 is known as the Black Canyon Freeway from the northern end of the Phoenix Metropolitan Area to a point 2.2 miles (3.5 km) south of The Stack interchange with I-10 northwest of Downtown Phoenix . (It is accompanied by frontage roads for most of this portion, and they carry the Black Canyon Highway name to distinguish from
20000-753: The maximum speed limit is 75 mph (120 km/h) in northern Maine, varies between 50 and 70 mph (80 and 115 km/h) from southern Maine to New Jersey, and is 50 mph (80 km/h) in New York City and the District of Columbia. Currently, rural speed limits elsewhere generally range from 65 to 80 miles per hour (105 to 130 km/h). Several portions of various highways such as I-10 and I-20 in rural western Texas, I-80 in Nevada between Fernley and Winnemucca (except around Lovelock) and portions of I-15 , I-70 , I-80 , and I-84 in Utah have
20160-498: The mountains south of Cedar City and, again, north of Cove Fort. From Las Vegas , Nevada , I-15 winds and slightly inclines through the Virgin River Gorge in northwest Arizona , then it crosses the border into Utah and Washington County . Just past the border, there is a port of entry on each side of the freeway. These ports of entry ( weigh stations ) are jointly operated by the states of Utah and Arizona and are
20320-507: The north side of that city ( SR-271 ). Continuing northeast, it reaches the next pair of rest areas before an interchange with SR-20 and then a ranch exit (exit 100) before leaving Iron County. As I-15 enters Beaver County , the Interstate turns northwestward and winds its way through the mountain pass before heading north again to pass along the western edge of the city of Beaver . The southern and northern interchanges in Beaver include
20480-447: The north-northwest before reaching the interchange with the northern end of SR-28 about a mile (1.6 km) north of town. The Interstate then turns north and passes by the eastern side of Mona and has an interchange with SR-52 (300 North). Continuing north, it passes by the eastern edge of Rocky Ridge before promptly leaving Juab County and entering Utah County . As the freeway enters Utah County, it also enters Utah Valley ,
20640-547: The northern border of Perry and the southern border of Brigham City . (US 91 continues northeast to Logan and points northward.) Curving slightly to the west, the Interstate reaches the Forest Street interchange, followed by the 900 North ( SR-13 ) interchange. Immediately north of 900 North, the freeway passes immediately to the west of the Brigham City Airport . West of the airport, there
20800-471: The northern end of the overlap with US 6. (The section between Spanish Fork and Lehi was rebuilt in 2010–2012 as part of the I-15 CORE project .) Continuing north with four lanes, it gains an additional express lane in both directions. It then passes through the far west side of Springville , with interchanges at 400 South ( SR-77 ) and 1400 North ( SR-75 ). Off the 1400 North interchange
20960-605: The northwestern side of the town of Leeds , with one-way interchanges on the southwest and northeast ends of town. After passing through the northwestern part of Toquerville , and an interchange with SR-17 (at Anderson Junction ), I-15 resumes a more north-northeastern course as it ascends about 1,000 feet (300 m) higher on the Colorado Plateau . Along the way, it passes through the areas of Browse and Pintura , with interchanges at both, as well as two more ranch exits further northeast. After its ascent, it passes by
21120-404: The number of fatalities on the Interstate Highway System amounted to more than 5,000 people annually, with nearly 5,600 fatalities in 2022. The United States government's efforts to construct a national network of highways began on an ad hoc basis with the passage of the Federal Aid Road Act of 1916 , which provided $ 75 million over a five-year period for matching funds to the states for
21280-443: The numbered system of U.S. highways was created, this route was signed US 91 . The route of I-15 from St. George to Brigham City was built along the corridor of what was US 91 from 1926 to 1974. In 1974, I-15 was reasonably intact and US 91 was deleted, with the unfinished segments signed as Temporary I-15. The route north of Brigham City was built along the corridor of an old routing of US 191 . This highway
21440-532: The official Interstate Highway standards . On one- or two-digit Interstates, the mile marker numbering almost always begins at the southern or western state line. If an Interstate originates within a state, the numbering begins from the location where the road begins in the south or west. As with all guidelines for Interstate routes, however, numerous exceptions exist. Interstate 15 in Utah Interstate ;15 ( I-15 ) runs north–south in
21600-561: The original Interstate Highway System was proclaimed complete in 1992, despite deviations from the original 1956 plan and several stretches that did not fully conform with federal standards . The construction of the Interstate Highway System cost approximately $ 114 billion (equivalent to $ 618 billion in 2023). The system has continued to expand and grow as additional federal funding has provided for new routes to be added, and many future Interstate Highways are currently either being planned or under construction. Though heavily funded by
21760-656: The planning phase between them. In 1966, the FHWA designated the entire Interstate Highway System as part of the larger Pan-American Highway System, and at least two proposed Interstate expansions were initiated to help trade with Canada and Mexico spurred by the North American Free Trade Agreement (NAFTA). Long-term plans for I-69 , which currently exists in several separate completed segments (the largest of which are in Indiana and Texas ),
21920-411: The prefix H . There are three one-digit routes in the state ( H-1 , H-2 , and H-3 ) and one auxiliary route ( H-201 ). These Interstates connect several military and naval bases together, as well as the important communities spread across Oahu, and especially within the urban core of Honolulu . Both Alaska and Puerto Rico also have public highways that receive 90 percent of their funding from
22080-424: The route between Phoenix and Cordes Junction ) from exit 242 south of town at a diamond interchange to another diamond interchange at exit 244 north of town. The business route was subsequently transferred from state to local maintenance and because of ADOT's policy of not signing business loops on nonstate maintained roadways, the route was decommissioned in 2011. Major intersections The entire route
22240-537: The route, without regard to the route number. For instance, I-190 in Massachusetts is labeled north–south, while I-195 in New Jersey is labeled east–west. Some looped Interstate routes use inner–outer directions instead of compass directions, when the use of compass directions would create ambiguity. Due to the large number of these routes, auxiliary route numbers may be repeated in different states along
22400-419: The same numbers, which is generally disallowed under highway administration guidelines. Several two-digit numbers are shared between unconnected road segments at opposite ends of the country for various reasons. Some such highways are incomplete Interstates (such as I-69 and I-74 ) and some just happen to share route designations (such as I-76 , I-84 , I‑86 , I-87 , and I-88 ). Some of these were due to
22560-503: The same roadway are signed as traveling in opposite directions; one such wrong-way concurrency is found between Wytheville and Fort Chiswell , Virginia, where I‑81 north and I‑77 south are equivalent (with that section of road traveling almost due east), as are I‑81 south and I‑77 north. Auxiliary Interstate Highways are circumferential, radial, or spur highways that principally serve urban areas . These types of Interstate Highways are given three-digit route numbers, which consist of
22720-603: The southern 4.16 miles (6.69 km) are part of the Maricopa Freeway . The portion of the highway south of Cordes Lakes was built along the alignment of State Route 69 (SR 69), while the northern part was built along old SR 79 's alignment. The final section of I-17 was completed in 1978. I-17 gains more than one mile (1.6 km) in elevation between Phoenix at 1,117 feet (340 m) and Flagstaff at 7,000 feet (2,100 m). The highway features several scenic view exits along its route that overlook
22880-522: The southernmost rest areas along its route within the state (with one each, northbound and southbound). After passing about a mile (1.6 km) west of Kanarraville, it reaches an interchange in Hamilton Fort . The freeway then briefly turns nearly east before turning north again to pass through the west side of Cedar City . The first interchange is at the southern end of SR-130 (Main Street) and
23040-626: The southwestern part of town and North Main Street / Cedar Mountain Road on the northern city limits. Off the North Main Street interchange, there is an official rest stop courtesy of UDOT and the local Chevron Station. Continuing north-northwest, it has an interchange with 5400 North / Maple Hollow Road ( SR-64 ) before passing by the southeast edge of Holden . Several miles northeast of Holden, US 50 merges with I-15 as it continues northeastward and eventually heading through
23200-437: The state. (The route of Old US 91, in turn, followed the older Arrowhead Trail highway to Salt Lake City .) After leaving St. George, I-15 continues northeast and passes through the northern part of the city of Washington . An auxiliary lane is added between St. George Boulevard and Green Springs Road with additional interchanges at Washington Parkway and State Street ( SR-9 ). Northeast of Washington, I-15 passes through
23360-399: The unconstructed sections was estimated. After the entire length of the freeway was completed, there was a discrepancy of an extra three miles (4.8 km) along all sections north of Nephi. UDOT had been aware of the problem for many years but delayed corrective action for the issue.) The following year, in 2005, UDOT renumbered the exits to correspond to the corrected mile markers. The result
23520-495: The war, complied by submitting a detailed network of 20,000 miles (32,000 km) of interconnected primary highways—the so-called Pershing Map . A boom in road construction followed throughout the decade of the 1920s, with such projects as the New York parkway system constructed as part of a new national highway system. As automobile traffic increased, planners saw a need for such an interconnected national system to supplement
23680-461: The way. The first is with Highland Drive / 14600 South ( SR-140 ). The next interchange is with Bangerter Highway ( SR-154 ). The third interchange in Draper is with 12300 South (US 89 / SR-71 ). This interchange is also where US 89 ends its first overlap with the Interstate and where I-15 curves slightly to the west. The final interchange in town is on the northern city limits at 11400 South ( SR-175 ). This interchange
23840-848: Was also complete. The largest section yet to be completed was from SR 179 north to Flagstaff. This segment was still just a two-lane roadway, but it did have full traffic interchanges built at crossroads. The portion from I-40 south to the Flagstaff Municipal Airport had been completed by this time. The final section of I-17, near Camp Verde and Montezuma Castle, began construction in February 1977 and opened to traffic in August 1978. In 1993, officials in Arizona proposed an extension of I-17 to connect with I-15 in Utah . The existing interchange with Happy Valley Road in Phoenix
24000-449: Was also deleted once I-15 was reasonably intact. However, a different route in Utah was redesignated US 191 in 1982. Also, by the time it completed the section, UDOT recalibrated the mileposts and renumbered the exits, reducing the overall distance by approximately three miles (4.8 km). In 1975, UDOT would construct a wildlife crossing located near the town of Beaver. The Utah Division of Wildlife Resources considers this to be
24160-464: Was converted to a diverging diamond interchange (DDI). The project was finished in the fall of 2020. I-17 has the unusual distinction of starting at approximately milepost 194 instead of at milepost 0. This is a holdover from Arizona's old system of marking mileposts, where a branching route would continue the milepost numbering of its original host, instead of starting over at zero. I-17 inherited its milepost locations from SR 69 , which
24320-495: Was designated by the Utah Legislature in 1998 as the Veterans Memorial Highway . In 2004, UDOT finally renumbered the mile markers along I-15 north of Nephi . (When I-15 was originally built, there were several large gaps along the route, including south of Nephi. In addition, the original plans for I-15 were to run along the west side of Nephi, instead of the final alignment along the city's east side. Mileage along
24480-551: Was employed ahead of Hurricane Charley in the Tampa, Florida area and on the Gulf Coast before the landfall of Hurricane Ivan ; however, evacuation times there were no better than previous evacuation operations. Engineers began to apply lessons learned from the analysis of prior contraflow operations, including limiting exits, removing troopers (to keep traffic flowing instead of having drivers stop for directions), and improving
24640-541: Was established as a state route from Phoenix north to Prescott . The road was completed by 1940 to Prescott. In 1954, a new route north to Flagstaff was established as SR 79. In May 1956, the Black Canyon Highway from Phoenix to Flagstaff was completed, but not to Interstate standards. It was incorporated into the new Interstate Highway System , established by the federal government later that year, and designated as part of I-17. The first interchange on
24800-414: Was exit numbers north of Nephi were reduced by three. In January 2009, the speed limit on two sections of I-15 together totaling 34 miles (55 km) was raised to 80 mph (130 km/h) as a "test", making Utah the second state to currently have speed limits greater than 75 mph (121 km/h). In September 2013, with a few brief exceptions, the speed limit north of Leeds (other than
24960-594: Was expanded to three lanes from I-15 to Bingham Blvd in both directions and the Union Pacific Rail Road Bridge (USRR) over 7200 South was reconstructed. The I-15 portion of this project started in the spring of 2018. A new general purpose lane from 7800 South to 12300 South was completed in December ;2018 and the new general purpose lane from SR-201 to 7200 South was completed in 2020. The Utah Department of Transportation
25120-828: Was in Black Canyon City . Interstate Highway [REDACTED] The Dwight D. Eisenhower National System of Interstate and Defense Highways , commonly known as the Interstate Highway System , or the Eisenhower Interstate System , is a network of controlled-access highways that forms part of the National Highway System in the United States . The system extends throughout the contiguous United States and has routes in Hawaii , Alaska , and Puerto Rico . In
25280-422: Was proclaimed complete in 1992, but two of the original Interstates— I-95 and I-70 —were not continuous: both of these discontinuities were due to local opposition, which blocked efforts to build the necessary connections to fully complete the system. I-95 was made a continuous freeway in 2018, and thus I-70 remains the only original Interstate with a discontinuity. I-95 was discontinuous in New Jersey because of
25440-494: Was serving as Supreme Commander of Allied Forces in Europe during World War II . In 1954, Eisenhower appointed General Lucius D. Clay to head a committee charged with proposing an interstate highway system plan. Summing up motivations for the construction of such a system, Clay stated, It was evident we needed better highways. We needed them for safety, to accommodate more automobiles. We needed them for defense purposes, if that should ever be necessary. And we needed them for
25600-474: Was the last section of I-15 in Utah County to be reconstructed in recent years. The actual construction elements included was based on the results of the ongoing engineering, traffic, and cost analysis. Those elements include I-15 reconstructed and widened with two new lanes in each direction from Lehi Main Street to SR-92, a one-way frontage road system from 2100 North to SR-92, interchange reconstruction at SR-92 and 2100 North, 13 bridge replacements,
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