Interstate 15 in Arizona
Template:Infobox Interstate/Intrastate Interstate 15 is an Interstate Highway that passes through Mohave County in the far northwest corner of the U.S. state of Arizona. Despite its short length of about 30 miles (50 km), and its isolation from the rest of the state in the remote Arizona Strip, it is notable for the scenic section through the Virgin River Gorge, the most expensive section of rural Interstate per mile when it opened.
Route description
I-15 parallels the Virgin River for its entire length in Arizona, but the terrain abruptly becomes more rugged northeast of Littlefield, where the Virgin River Gorge begins.[1]
The highway enters the state just northeast of Mesquite, Nevada, paralleling the old U.S. Route 91 on an alignment north of the river. The first interchange is exit 8 at Littlefield, where old US 91 turns north to avoid the gorge. I-15 crosses the river for the first time just beyond Littlefield, and passes another interchange serving local roads east of Littlefield. This exit, exit 9, is a right-in/right-out design, with collector/distributor roads keeping slow traffic off I-15, and was constructed after the initial opening of I-15. Access under I-15 is provided just south of the ramps.[1]
Beyond exit 9, I-15 enters the Virgin River Gorge, first passing through the section known as "The Narrows". Within the canyon, through which it ascends northbound and descends southbound, four bridges cross or travel above the river.[2] The highway generally follows the winding course of the river, but several rock cuts allow it to bypass bends.[1]
The canyon opens up slightly at the Cedar Pocket interchange (exit 18), allowing for a rest area. I-15 continues to parallel the Virgin River, but deviates more than through the narrower part of the canyon. At mile 22.5, the highway crosses the Virgin River for the final time, continuing east along the smaller Black Rock Gulch before turning slightly northeast into a flatter area. The final interchange - exit 27 - provides local access, and an agricultural inspection station formerly served both sides of the road before the Utah state line.[1]
History
The Old Spanish Trail to Southern California had two routes through northwestern Arizona, splitting at Littlefield; one went north towards central Utah, and the other went northeast through the Virgin River Gorge, straddling the state line to the Four Corners area.[3] When the Arrowhead Trail was marked in the 1920s, and U.S. Route 91 in 1926, automobile travelers between Nevada and Utah were routed via the northerly routing, turning east in Utah to reach St. George.[4]
When the Interstates were planned, the decision was made to save 12 miles (19 km) over US 91[5] and pass through the scenic Virgin River Gorge. Construction was completed first, in the early 1960s, on the portion between Nevada and the gorge; I-15 was fully opened through the gorge on December 14, 1973. Even before its opening, it was promoted as the most scenic highway in the state; a 1988 article in Arizona Highways said that the project "enhanced rather than distracted from Nature's handiwork". The Virgin River was rechanneled 12 times in what was, at the time, the most expensive rural freeway in the country, costing about $10 million per mile.[5][6][7]
Exit list
The entire route is in Mohave County.
| Mile[8] | # | Destinations | Notes |
|---|---|---|---|
| 8.61 | 8 | Littlefield, Beaver Dam (Littlefield Road) | Old US 91 |
| 9.63 | 9 | Farm Road | |
| 18.35 | 18 | Cedar Pocket Road | Rest area at this exit |
| 27.49 | 27 | Black Rock Road |
References
- ^ a b c d United States Geological Survey topographic maps, accessed via Terraserver-USA
- ^ Arizona Department of Transportation, Arizona State Highway System Bridge Record, as of March 27, 2007
- ^ National Park Service, Old Spanish National Historic Trail, accessed August 9, 2007
- ^ Rand McNally Auto Road Atlas, 1926, accessed via the Broer Map Library
- ^ a b Fresno Bee, Costliest Rural Freeway - $100 An Inch, November 26, 1972
- ^ Federal Highway Administration, Previous Interstate Facts of the Day, May 30, 2007
- ^ Federal Highway Administration, Final List of Nationally and Exceptionally Significant Features of the Federal Interstate Highway System, accessed August 9, 2007
- ^ Arizona Department of Transportation. "ADOT Highway Log" (PDF).
{{cite web}}: Unknown parameter|accessmonthday=ignored (help); Unknown parameter|accessyear=ignored (|access-date=suggested) (help)
