article

Interstate 15 (abbreviated I-15) is the fourth longest north-south transcontinental interstate highway in the United States, traveling through the states of Montana, Idaho, Utah, Arizona, Nevada, and California. In California, this freeway is a major transportation corridor linking the San Diego-Carlsbad-San Marcos Metropolitan area with the Riverside-San Bernardino-Ontario Metropolitan area, and various suburban communities between them. It is also the main artery of transportation through the Salt Lake City Metropolitan area. It also serves as the primary access route from Southern California to Las Vegas, Nevada, a major travel/tourist destination throughout the year. More recently, I-15 has begun to serve as a heavily traveled commuter route between the Mojave Desert communities of Victorville, Hesperia, Apple Valley, and Adelanto in California, due to rapid population growth and associated residential, commercial, and industrial development.

The I-15 corridor between Los Angeles and Las Vegas has long been proposed as a maglev train route; in 2004 the California-Nevada Interstate Maglev project held public meetings on the plan. *

Route Summary

This highway's beginning is in San Diego, California at the Interstate 8 merge, 18 miles north of the international border with Mexico. However, work is being done to extend this to Interstate 5 (the current work on this extension is signed California State Highway 15). The northern terminus is in Sweetgrass, Montana at the international border between the United States and Canada, where it becomes Alberta provincial highway 4.

California

North of its junction with the Riverside Freeway, State Route 91, in the Inland Empire near Corona, the route follows (roughly) the old U.S. Highway 91. North of Devore, California the highway follows the approximate alignment of historic U.S. Highway 66 until about the Mojave River 35 miles (56 km) to the north. For many parts of the highway, high-voltage power lines follow the freeway, many of them link distant power stations to the Los Angeles metro area.

Interestingly, the starting point of Interstate 15 was originally planned to be in San Bernardino at an interchange with the San Bernardino Freeway, Interstate 10 (I-10). This was logical as I-15 was following the old alignment of the historic route U.S. Route 66 which passed through San Bernardino. The segment was completed accordingly. However, legislation was later passed to extend the interstate to San Diego. But instead of extending the existing freeway from the I-10 interchange south, the California Department of Transportation created a new segment in Devore that 'branched' off of the original alignment and bypassed San Bernardino altogether. This segment's alignment is generally northeast to southwest for about 15 miles (24 km). Then, in Fontana/Rancho Cucamonga, California, its directional alignment shifts to north-south where it eventually junctions with Interstate 10 (about 15 miles west of the original interchange in San Bernardino). The segment that had been built from Devore to San Bernardino was retained as an interstate, but was re-numbered as Interstate 215. Note that during the construction of I-15's present alignment, and for some time afterwards, I-215 was numbered as I-15E.

See Interstate 215 (California)

There are three bypasses and loops identified as Interstate 215: in the Inland Empire region of California, Las Vegas, and Salt Lake City.

In California, I-15 has at least five different names throughout its length. From its beginning to the Riverside/San Diego county line, it is named the Escondido Freeway. The portion of the Escondido Freeway passing through the Marine Corps Air Station at Miramar is also known as the Semper Fi Highway. From the San Diego county line to State Route 74 (the Ortega Highway) in Lake Elsinore, it is named the Temecula Valley Freeway. From CA/SR-74 to Limonite Avenue in Riverside County, it is known as the Corona Freeway. From Limonite Avenue to the northern junction with I-215 spur in Devore, it is named the Ontario Freeway. From the northern I-215 junction to the Interstate 40 junction in Barstow, California, it is named the Barstow Freeway. Finally, from Barstow to the California/Nevada state line it is named the Mojave Freeway.

State law
Legal Definition of Route 15: California Streets and Highways Code, Chapter 2, Article 3, Section 315

Nevada

Interstate 15 in Nevada begins in Primm. It continues through Las Vegas, Nevada. Finally, it crosses the border with Arizona in Mesquite.

Arizona

I-15 just clips the northwestern corner of Arizona with a total mileage of less than 30. The stretch is separated from the rest of the state and has no major exits or junctions. It includes a spectacular section where the road twists between the narrow walls of the Virgin River gorge (ascent northbound, descent southbound).

Utah

I-15 continues through Utah with a mileage of just over 400. It is the main north-south connection for the state. The highway approximately follows the old alignment of U.S. Highway 91 from St. George to Brigham City. The highway passes through the fast-growing Dixie region, which includes St. George, 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, Interstate 70 begins its journey eastward across the country. The interstate merges with I-80 for about 3 miles from South Salt Lake to just west of Downtown Salt Lake City and also merges with Interstate 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 (the Wasatch Range in the northern half of the state). The only exceptions are when it passes through the mountains south of Cedar City and again north of Cove Fort.

Idaho

I-15 passes through Idaho for nearly 200 miles. The highway runs through Pocatello, Blackfoot, and Idaho Falls. It also merges with Interstate 86.

Montana

Interstate 15 continues onward through nearly 400 miles of Montana through the cities of Butte, Helena and Great Falls, intersecting with Interstate 90, Interstate 115 and Interstate 315. Interstate 15 reaches its northern termninus at the International Border with Alberta, Canada.

Length

Mileskmstate
287 462 California
124 200 Nevada
29 47 Arizona
401 645 Utah
196 315 Idaho
396 637 Montana
1,433 2,307 Total

Major cities

Bolded cities are officially-designated control cities for signs.

Major intersecting freeways and highways

Listed in order from south to north:

California

Nevada

Arizona

Interstate 15 does not intersect any major roads in Arizona.

Utah

Idaho

Montana

Spur routes

Notes

  • Managed Lanes Project- Initated during fall 2003 and will finish late 2007. Portion of CA-56 to Centre City Pkwy (former US 395). More info in "reference" section; See also high occupancy toll.
  • At the time it was built, the section running through the northwest corner of Arizona (the Virgin River gorge) was the most expensive section (per mile) of the entire interstate system.
  • The sign for the Zzyzx exit, the alphabetically last place name in the United States, is a well-known landmark along the drive from Los Angeles to Las Vegas on I-15.
  • Interstate 15 had an eastern branch bypassing San Bernardino, California, and a western branch in Idaho. I-215 around San Bernardino was I-15E, and the western I-86 was once called I-15W.
  • The eastern section of I-215 in Salt Lake City, from the south interchange with I-15 east to I-80, was once known as I-415.
  • I-15 ends at the border between Montana and Alberta, where it becomes Alberta provincial highway 4. Combined with Alberta provincial highway 3 and Alberta provincial highway 2, this route can be used to go into the cities of Calgary and Edmonton and other Alberta cities.

Reference and External links

  • http://www.ihoz.com/interstates.html
  • http://www.dot.ca.gov/dist11/facts/I-15managed.pdf
  • 2005 Rand McNally "The Road Atlas 2005" - newest feature- interstate mileage by state
  • Interstate 15 at Larry's Phat Page

California

Arizona

Interstate Highway System | Interstate Highways in Arizona | Interstate Highways in California | California Freeway and Expressway System | Interstate Highways in Idaho | Interstate Highways in Montana | Interstate Highways in Nevada | Interstate Highways in Utah | U.S. Route 66

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Interstate 15".

Home Page • arts • business • computers • games • health • hospitals • home • kids & teens • news • physicians • recreation• reference • regional • science • shopping • society • sports • world