Interstate 70 in Utah
Interstate 70 is a mainline route of the Interstate Highway System in the United States connecting Utah and Maryland. The Utah section runs east–west for approximately across the central part of the state. Richfield is the largest Utah city served by the freeway, which does not serve or connect any urban areas in the state. The freeway was built as part of a system of highways connecting Los Angeles and the Northeastern United States. I-70 was the second attempt to connect southern California to the east coast of the United States via central Utah, the first being a failed attempt to construct a transcontinental railroad. Parts of that effort were reused in the laying out of the route of I-70.
Unlike most Interstate Highways, much of I-70 in Utah was not constructed parallel to or on top of an existing U.S. Route. Portions of I-70 were constructed in areas where previously there were no paved roads. Because it was built over an entirely new route, I-70 has many features that are unique in the Interstate Highway System. For example, the stretch between Green River and Salina makes up the longest distance anywhere in the Interstate Highway System with no motorist services. This same piece is noted as the longest highway in the United States built over a completely new route since the Alaska Highway, and the longest section of Interstate Highway to open at a given time. The construction of the Utah portion of I-70 is listed as one of the engineering marvels of the Interstate Highway System.
The choice of the route had a significant impact on the character and culture of the Sevier Valley. It has also been a motivating factor for environmentalists to create a new national park along the path of the highway to protect scenic areas around the route. I-70 from Green River to Grand Junction, Colorado, is part of the Dinosaur Diamond Prehistoric Highway, making I-70 one of the few Interstate Highways to be named a National Scenic Byway. Attractions listed by the Federal Highway Administration for the Dinosaur Diamond Prehistoric Highway on or near I-70 include, Arches National Park, Canyonlands National Park, Cleveland-Lloyd Dinosaur Quarry, Goblin Valley State Park, Ruby Canyon, and Westwater Canyon. The designation also lists several side roads branching from I-70 that lead to dinosaur bones, footprints, and native petroglyphs.
Route description
I-70 begins at a trumpet interchange with I-15, near Cove Fort. It then proceeds east over the Pahvant Range, cresting at Clear Creek Summit with an elevation of. The eastern descent from the Pahvant Range features bridges high above Clear Creek and its side canyons. The longest of these bridges is the Fish Creek bridge at long. The descent into Clear Creek features a brake check area and runaway truck ramp to aid truckers down the steep slope. The freeway then skirts the edge of Fremont Indian State Park and Museum before entering Sevier Valley.Sevier Valley
I-70 serves as the main thoroughfare of the valley, the only area traversed by the highway in Utah with more than a few hundred residents. Richfield is the largest city along I-70 in the state. The highway enters the valley just north of Big Rock Candy Mountain, a mountain named for a song attributed to Harry McClintock. The highway proceeds northeast along the western edge of the valley, passing to the west of the communities of the valley, including Joseph, Monroe, Elsinore, and Richfield. As I-70 approaches Salina, it cuts across the valley passing to the south of the town. The highway avoids the downtown areas of all of these cities. The portion between Richfield and Salina is the busiest, with an annual average daily traffic of 11,535 vehicles in 2006. In the Sevier Valley, I-70 was built parallel to U.S. Route 89; both highways now run concurrently between exit 23 and exit 56 in Salina.Wasatch Plateau
At Salina, US-50 joins I-70, and the two highways run concurrent for the rest of the way through Utah. After leaving exit 56 in Salina, I-70 departs on a course to the first Green River offramp, exit 160. Though there are a number of exits in between the two cities, it is the longest distance in the Interstate Highway System with no motorist services directly along the highway. The route to Green River crosses two major geographic obstacles: the Wasatch Plateau and the San Rafael Swell.I-70 initially begins an ascent up the Wasatch Plateau via Salina Canyon. At lower elevations, this canyon separates the Wasatch Plateau to the north with the Sevier Plateau to the south. After climbing to a fork in the canyon, the highway turns south and crests the Wasatch Plateau at Emigrant Pass. This pass is the highest point of any of Utah's Interstate Highways, although the elevation differs from source to source. Newer Utah Department of Transportation maps list the elevation of, while older maps give the figure. This portion of I-70 is on protected lands as part of Fishlake National Forest. The highway exits the Wasatch Plateau at Fremont Junction, where I-70 meets Utah State Route 10.
San Rafael Swell
Between Fremont Junction and the junction of SR-24 near Green River, I-70 crosses a geologic feature called the San Rafael Swell. The construction of the highway through the swell is listed as one of the engineering marvels of the Interstate Highway System, with one engineer claiming this section as "one of the most significant highway construction feats of its time". The construction of I-70 through the swell required boring through many solid rock canyons, cliffs, and mountains. The swell is noted for its sheer canyons and rock formations and is home to a large amount of exposed dinosaur remains. This includes the largest known collection of Jurassic-period dinosaur remains at the Cleveland-Lloyd Dinosaur Quarry at the north end of the swell.The highway ascends the western edge of the swell on a steady slope loosely following the north rim of Devils Canyon. At the top of the grade is a view area with a view of Devils Canyon and an overlook of the landscape west of the swell. It then crosses Eagle Canyon via a pair of steel arch bridges. The eastbound bridge is long, and the westbound bridge is long.
The highway then ascends Ghost Rock Summit, named for unusual rock formations nearby, and the highest point for I-70 inside the swell. At the summit is another view area overlooking the Little Grand Canyon of the San Rafael River. The Ghost Rocks themselves are at, although the freeway is slightly lower. I-70 meanders through a relatively flat portion of the swell until reaching Spotted Wolf Canyon, which provides the exit route to the swell. The eastern descent features one brake check area and two runaway truck ramps to aid trucks down. About halfway down is a view area of the canyon narrowing as it approaches the eastern escarpment of the swell, the San Rafael Reef. Just as the highway exits the swell near Green River, it passes to the north of Goblin Valley State Park.
Book Cliffs
West of Green River, US-6 and US-191 join I-70. Also at Green River, the freeway reaches the southern edge of the Book Cliffs, a mountain range which I-70 follows to Grand Junction, Colorado. This portion of I-70 is part of the Dinosaur Diamond Prehistoric Highway, recognized as a scenic byway by both the National Scenic Byways and Utah Scenic Byways programs. Listed attractions along the byway in the Green River area include Crystal Geyser, Capitol Reef National Park, and Green River State Park.From this point east, the freeway is routed across a flat area between the Book Cliffs and the Colorado River, called Sagers Flat. Along the way, it passes by the towns of Crescent Junction, Thompson Springs, and the ghost town of Cisco. Natural features visible from this portion include Arches National Park and Castle Valley. Other listed attractions along the byway near this section include Canyonlands National Park and various areas with Morrison Formation, a layer of rock where dinosaur remains are common. I-70, US-6, and US-50 all enter Colorado concurrently. Where I-70 follows the Book Cliffs, it was built parallel to or on top of US-6/US-50.
History
Old Spanish Trail
The first route through this portion of Utah was the Old Spanish Trail, a trade route between Santa Fe, New Mexico, and Los Angeles, California. The trail was in common use before the Mexican–American War in 1848. Although the trail serves a different route than I-70, they were both intended to connect Southern California with points further east. I-70 generally parallels the route of the Old Spanish Trail west of Crescent Junction. I-15 south of the junction with I-70 also generally parallels the trail.Transcontinental railroads
The first attempt to build a modern trade route through the area is credited to William Jackson Palmer, founder of the Denver and Rio Grande Western Railroad. Palmer started a project in 1880 to make what had been a local railroad from Colorado into a transcontinental railroad empire. This would mean a second transcontinental railroad would be built across Utah. This would also place the D&RG in competition with the first transcontinental railroad, then operated by the Union Pacific Railroad and Central Pacific Railroad.Disagreements in the company led to two proposals. Both proposals called for extending the railroad west from Colorado as far as what is now Green River. West of Green River, a "northern route" would extend the railroad towards Ogden, Utah, there connecting with the established Overland Route. This proposal was eventually completed as the Utah Division, loosely following the route of modern US-6 across eastern Utah. This line soon became the main line of the D&RG and remains one of the main transcontinental rail arteries of the US, now operated by the Union Pacific Railroad as the Central Corridor.
The second proposal was a "southern route" that would continue due west from Green River and head toward Los Angeles, similar to the route of modern I-70. This proposal would require extending the railroad farther west, to connect with what would become the Los Angeles and Salt Lake Railroad.
Due to disagreements in management and poor communication, construction began on both routes. It was soon obvious that the southern route was unfeasible given the remote area, technology available at the time, and the rough terrain of the San Rafael Swell. In 1883, the D&RG spent $217,470 on the project before declaring it a failure. One of the accounts in the book Utah Ghost Rails states the railroad fired the lead surveyor, even though the workers had graded a path past the San Rafael Reef. This route today is a jeep trail. According to a sign placed by the Bureau of Land Management, had the southern route succeeded, it would have been the shortest transcontinental railroad in the US.
Construction resumed in 1901 on a portion of the southern route, to build a spur line to service coal mines on the Wasatch Plateau. The railroad branched from an existing line at Salina and traveled east up Salina Canyon. After the mines closed, the railroad bed was used to improve SR-10, between Salina and Fremont Junction. I-70 would later use the railroad bed for a path across the Wasatch Plateau.