Interstate 70 in Colorado

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Interstate 70 marker

Interstate 70
I-70 runs east-west through Colorado, intersecting a north-south Interstate near Denver, from where a third Interstate heads northeast.
Interstate Highways in Colorado with I-70 in red
Route information
Maintained by CDOT
Length 449.589 mi[1] (723.543 km)
History Designated in 1956
Completed in 1992
Major junctions
West end I-70 / US-6 / US-50 at Utah state line
East end I-70 / US-24 at Kansas state line
Highway system
Colorado State Highways
SH 69 SH 71

Interstate 70 (I-70) is a transcontinental Interstate Highway in the United States, stretching from Cove Fort, Utah, to Baltimore, Maryland. In Colorado, the highway traverses an east–west route across the center of the state; in western Colorado, the highway connects the metropolitan areas of Grand Junction and Denver via a route through the Rocky Mountains. In eastern Colorado, the highway crosses the Great Plains, connecting Denver with metropolitan areas in Kansas and Missouri. Bicycles and other non-motorized vehicles, normally prohibited on Interstate Highways, are allowed on those stretches of I-70 in the Rockies where no other through route exists.

The U.S. Department of Transportation (USDOT) lists the construction of I-70 among the engineering marvels undertaken in the Interstate Highway system, and cites four major accomplishments: the section through the Dakota Hogback, Eisenhower Tunnel, Vail Pass and Glenwood Canyon. The Eisenhower Tunnel, with a maximum elevation of 11,158 feet (3,401 m) and length of 1.7 miles (2.7 km), is the longest mountain tunnel and highest point along the Interstate Highway System. The portion through Glenwood Canyon was completed on October 14, 1992, this was one of the final pieces of the Interstate Highway System to open to traffic, and is one of the most expensive rural highways per mile built in the United States. The Colorado Department of Transportation (CDOT) earned the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers for the completion of I-70 through the canyon.

When the Interstate Highway system was in the planning stages, the western terminus of I-70 was proposed to be at Denver, the portion west of Denver was included into the plans after lobbying by Governor Edwin C. Johnson, for whom one of the tunnels along I-70 is named. East of Idaho Springs, I-70 was built along the corridor of U.S. Highway 40, one of the original transcontinental U.S. Highways. West of Idaho Springs, I-70 was built along the route of U.S. Highway 6, which was extended into Colorado during the 1930s.

Route description[edit]

A railroad, river and two-tiered highway following a narrow canyon
Westbound I-70 on a viaduct inside Glenwood Canyon paralleling the Colorado River and former Denver and Rio Grande Western Railroad (now Union Pacific) main line

Colorado River[edit]

I-70 enters Colorado from Utah, concurrent with US 6 and US 50, on a plateau between the north rim of Ruby Canyon of the Colorado River and the south rim of the Book Cliffs. The plateau ends just past the state line and the highway descends into the Grand Valley, formed by the Colorado River and its tributaries,[2] the Grand Valley is home to several towns and small cities that form the Grand Junction Metropolitan Statistical Area, the largest conurbation in the area regionally known as the Western Slope. The highway directly serves the communities of Fruita, Grand Junction and Palisade. Grand Junction is the largest city between Denver and Salt Lake City and serves as the economic hub of the area,[3] the freeway passes to the north of downtown, while US 6 and 50 retain their original routes through downtown. US 6 rejoins I-70 east of Grand Junction; US 50 departs on a course toward Pueblo.[2]

I-70 exits the valley through De Beque Canyon, a path carved by the Colorado River that separates the Book Cliffs from Battlement Mesa, the river and its tributaries provide the course for the ascent up the Rocky Mountains. In the canyon, I-70 enters the Beavertail Mountain Tunnel, the first of several tunnels built to route the freeway across the Rockies, this tunnel design features a curved sidewall, unusual for tunnels in the United States, where most tunnels feature a curved roof and flat side-walls. Engineers borrowed a European design to give the tunnel added strength,[4] after the canyon winds past the Book Cliffs, the highway follows the Colorado River through a valley containing the communities of Parachute and Rifle.[2]

Glenwood Canyon[edit]

East of the city of Glenwood Springs, the highway enters Glenwood Canyon. Both the federal and state departments of transportation have praised the engineering achievement required to build the freeway through the narrow gorge while preserving the natural beauty of the canyon.[4][5] A 12-mile (19 km) section of roadway features the No Name Tunnel, Hanging Lake Tunnel, Reverse Curve Tunnel, 40 bridges and viaducts, and miles of retaining walls.[6] Through a significant portion of the canyon, the eastbound lanes extend cantilevered over the Colorado River and the westbound lanes are suspended on a viaduct several feet above the canyon floor.[5][7] Along this run, the freeway hugs the north bank of the Colorado River, while the main line of the Union Pacific Railroad (formerly the Denver and Rio Grande Western) occupies the south bank.[2]

A pair of bridges leading to a pair of tunnels at the canyon wall
The western portal of the Hanging Lake Tunnel; at this point in the canyon both the river and railroad are directly below the freeway viaducts

To minimize the hazards along this portion, a command center staffed with emergency response vehicles and tow trucks on standby monitors cameras along the tunnels and viaducts in the canyon. Traffic signals have been placed at strategic locations to stop traffic in the event of an accident, and variable message signs equipped with radar guns will automatically warn motorists exceeding the design speed of one of the curves.[8] The USDOT makes provision for bicycles, which are usually prohibited along Interstate Highways, along the freeway corridor in Glenwood Canyon.[9]

Rocky Mountains[edit]

The highway departs the Colorado River near Dotsero, the name given to the railroad separation for the two primary mountain crossings, the original via Tennessee Pass/Royal Gorge and the newer and shorter Moffat Tunnel route.[10] I-70 uses a separate route between the two rail corridors, from this junction I-70 follows the Eagle River toward Vail Pass, at an elevation of 10,666 feet (3,251 m). In this canyon I-70 reaches the western terminus of U.S. Highway 24, which meanders through the Rockies before rejoining I-70. US 24 is known as the Highway of the Fourteeners, from the concentration of mountains exceeding 14,000 feet (4,300 m) along the highway corridor.[11] Along the ascent, I-70 serves the ski resort town of Vail and the ski areas of Beaver Creek Resort, Vail Ski Resort and Copper Mountain.[2]

Automobiles are driving on a road leading to one of two openings in a building against a mountain. Letters above each opening read "Johnson Tunnel 1979" and "Eisenhower Tunnel 1973". On the roof of the building, large ventilation hoods are visible.
Entrance to the Eisenhower Tunnel

The construction of the freeway over Vail Pass is also listed as an engineering marvel. One of the challenges of this portion is the management of the wildlife that roams this area. Several parts of the approach to the pass feature large fences that prevent wildlife from crossing the freeway and direct the animals to one of several underpasses, at least one underpass is located along a natural migratory path and has been landscaped to encourage deer to cross.[1][12]

The highway descends to Dillon Reservoir, near the town of Frisco, and begins one final ascent to the Eisenhower Tunnel, where the freeway crosses the Continental Divide. At the time of dedication, this tunnel was the highest vehicular tunnel in the world, at 11,158 feet (3,401 m).[13] As of 2010, the facility was still the highest vehicular tunnel in the United States,[6] the Eisenhower Tunnel is noted as both the longest mountain tunnel and highest point on the Interstate Highway System.[13] The tunnel has a command center, staffed with 52 full-time employees, to monitor traffic, remove stranded vehicles, and maintain generators to keep the tunnel's lighting and ventilation systems running in the event of a power failure. Signals are placed at each entrance and at various points inside the tunnel to close lanes or stop traffic in an emergency.[13] There are several active and former ski resorts in the vicinity of the tunnel, including Breckenridge Ski Resort, Keystone Resort, Arapahoe Basin, Loveland Ski Area, Berthoud Pass Ski Area and Winter Park Resort.[2]

Clear Creek[edit]

The freeway follows Clear Creek down the eastern side of the Rockies, passing through the Veterans Memorial Tunnels[14] near Idaho Springs. Farther to the east, I-70 departs the US 6 corridor, which continues to follow Clear Creek through a narrow, curving gorge. The interstate, however, follows the corridor of US 40 out of the canyon. The highway crests a small mountain near Genesee Park to descend into Mount Vernon Canyon to exit the Rocky Mountains,[2] this portion features grade-warning signs with unusual messages, such as "Trucks: Don't be fooled," "Truckers, you are not down yet," and "Are your brakes adjusted and cool?"[15] Runaway truck ramps are a prominent feature along this portion of I-70,[4] with a total of seven used along the descent of either side the Continental Divide to stop trucks with failed brakes.[1]

A highway near the top of a ridge. On either side of the highway are big yellow signs reading, "Trucks, Don't be Fooled—4 more miles of steep grades and sharp curves".
Warning sign stating, "Trucks, Don't be Fooled—4 more miles of steep grades and sharp curves."

The last geographic feature of the Rocky Mountains traversed before the highway reaches the Great Plains is the Dakota Hogback, the path through the hogback features a massive cut that exposes various layers of rock millions of years old. The site includes a nature study area for visitors.[4][16]

Great Plains[edit]

As the freeway passes from the Rocky Mountains to the Great Plains, I-70 enters the Denver metropolitan area, part of a larger urban area called the Front Range Urban Corridor, the freeway arcs around the northern edge of the LoDo district, the common name of the lower downtown area of Denver. Through the downtown area, US 40 is routed along Colfax Avenue, which served as the primary east–west artery through the Denver area before the construction of I-70. Through downtown, US 6 is routed along 6th Avenue before departing the I-70 corridor to join Interstate 76 on a northeast course toward Nebraska.[2] The freeway meets Interstate 25 in an interchange frequently called the Mousetrap.[4] From I-25 on to I-225, I-70 serves—together with those two Interstates—as part of an inner beltway around Denver.[17]

A city view with a pair of steel arch bridges in the foreground and various skyscrapers in the background.
Downtown Denver

I-70 has one official branch in Colorado, Interstate 270, which connects the interstate with the Denver–Boulder Turnpike. Where these two freeways merge is the busiest portion of I-70 in the state, with an annual average daily traffic of 183,000 vehicles per day.[18] While State Highway 470 and E-470 are not officially branches of I-70, they are remnants of plans for an I-470 outer beltway around Denver that were cancelled when the allocated funds were spent elsewhere.[19]

Leaving Denver, the highway serves the redevelopment areas on the former site of Stapleton International Airport; runway 17R/35L crossed over the Interstate at the runway's midsection.[2] East of Aurora, I-70 rejoins the alignment of U.S. Highway 40 at Colfax Avenue. The freeway proceeds east across the Great Plains, briefly dipping south to serve the city of Limon, which bills itself as Hub City because of the many rail and road arteries that intersect there.[20] I-70 enters Kansas near Burlington, a small community known for having one of the oldest carousels in the United States.[21]


As first proposed in 1944, the western terminus of I-70 was Denver, along the corridor of US 40. The portion across the Rocky Mountains was added to the plans, after lobbying by Colorado officials, following the US 6 corridor.[12] The origins of both the US 40 and US 6 pre-date the U.S. System of numbered highways, using established transcontinental trails.[22]

Earlier routes[edit]

Before the formation of the United States Numbered Highways, the U.S. relied on an informal network of roads, organized by various competing interests, collectively called the auto trail system. The surveyors of most trails chose either South Pass in Wyoming or a southern route through New Mexico to traverse the Rocky Mountains. Both options were less formidable than the higher mountain passes in Colorado, but left the state without a transcontinental artery. When the planners of the Lincoln Highway also decided to cross the Rockies in Wyoming, officials pressed for a loop to branch from the main route in Nebraska, enter Colorado, and return to the main route in Wyoming. While the Lincoln Highway was briefly routed this way, the loop proved impractical and was soon removed.[22]

A highway about to curve to the right while descending down a canyon
I-70 crossing the Rocky Mountains

After losing the connection to the Lincoln Highway, officials convinced planners of the Victory Highway to traverse the state, the highway entered Colorado from Kansas along what was previously called the Smoky Hill Trail. The highway crossed the mountains along a trail blazed by a railroad surveyor and captain in the American Civil War, cresting at Berthoud Pass,[22] after a round of political infighting between Utah and Nevada, the Victory Highway would become the Lincoln Highway's main rival for San Francisco-bound traffic.[23] When the U.S. Highway system was unveiled in 1926, the Victory Highway was numbered U.S. Highway 40.[22]

While US 6 was also one of the original 1926 U.S. Highways, the road originally served the portion of the United States east of the Rocky Mountains, the highway was not extended to the Pacific coast until 1937, mostly following the Midland Trail.[24] Around the time the U.S. Highway system was formed, the portion of the Midland Trail through Glenwood Canyon, known as the Taylor State Road, was destroyed by a flood.[22] When US 6 was extended, the Works Progress Administration was rebuilding the road through the canyon and the Public Works Administration was nearing completion of a new highway over Vail Pass.[12][22] In western Colorado, US 6 was routed concurrent with US 50 from the Utah state line to Grand Junction and eventually replaced US 24 from Grand Junction to near Vail.[25] To keep these routes over the Rockies competitive with alternatives in other states, the Colorado Department of Highways relied on ingenuity to keep the roads safe, the department pioneered new machines to clear snow and various bridge and culvert designs to protect the roads from flooding.[22]

Interstate Highway planning[edit]

A sharp curve with a cut in the mountain visible to support the highway
Interstate 70 descending into Clear Creek Canyon

Governor Edwin C. Johnson, for whom one of the tunnels along I-70 was later named, was a primary force in persuading the planners of the Interstate Highway System to extend the highway across the state. He stated to the Senate subcommittee:

You are going to have a four-lane highway through Wyoming. You are going to build two four-lane highways through New Mexico and Arizona. Colorado needs to be able to compete with our neighboring states. We do not want to take anything away from them. We do not want them to get way out ahead of us, either, because these interstate highways are going to be very attractive highways for the East and West to travel on.[12]

Colorado held several meetings to convince reluctant Utah officials they would benefit from a freeway link between Denver and Salt Lake City. Utah officials expressed concerns that, given the terrain between these cities, this link would be difficult to build, they later expressed concerns that the construction would drain resources from completing Interstate Highways they deemed to have a higher priority. Colorado officials persisted, presenting three alternatives to route I-70 west of Denver, using the corridors of US 40, US 6 and a route starting at Pueblo, proceeding west along US 50/US 285/US 24. In March 1955, Colorado officials succeeded in convincing Utah officials with the state legislature passing a resolution supporting a link with Denver, the two states jointly issued a proposal to the U.S. Congress that would extend the plans for I-70 along the US 6 corridor. Under this proposal the freeway would terminate at I-15 near Spanish Fork, Utah, linking the Front Range and Wasatch Front metropolitan areas.[12]

Beavertail Mountain tunnel as seen from the Amtrak California Zephyr

Congress approved the extension of I-70; however, the route still had to be approved by the representatives of the U.S. military on the planning committee. Military representatives were concerned that plans for this new highway network did not have a direct connection from the central U.S. to southern California; and further felt Salt Lake City was adequately connected. Military planners approved the extension, but moved the western terminus south to Cove Fort, using I-70 as part of a link between Denver with Los Angeles instead of Salt Lake City. Utah officials objected to the modification, complaining they were being asked to build a long and expensive freeway that would serve no populated areas of the state, after being told this was the only way the military would approve the extension, Utah officials agreed to build the freeway along the approved route.[12]


Several mountains with scars from roads visible at the base and up the sides
View from Loveland Pass, showing a hairpin turn along the US 6 alignment on top right, and the straighter I-70 emerging from the Eisenhower Tunnel on the left

The first Colorado portion of I-70 opened to traffic in 1961, this section bypassed and linked Idaho Springs to the junction where US 6 currently separates from I-70 west of the city. The majority of the alignment through Denver was completed by 1964, the Mousetrap reused some structures that were built in 1951, before the formation of the Interstate Highway system. The last piece east of Denver opened to traffic in 1977.[4]

Eisenhower Tunnel[edit]

Planning on how to route the freeway over the Rocky Mountains began in the early 1960s, the US 6 corridor crosses two passes: Loveland Pass, at an elevation of 11,992 feet (3,655 m) and Vail Pass, at 10,666 feet (3,251 m).[2] Engineers recommended tunneling under Loveland Pass to bypass the steep grades and hairpin curves required to navigate US 6. The project was originally called the Straight Creek Tunnel, after the waterway that runs along the western approach, the tunnel was later renamed the Eisenhower–Johnson Memorial Tunnel, after U.S. President Dwight D. Eisenhower and Colorado Governor Edwin C. Johnson.[13]

Construction on the first bore of the tunnel was started on March 15, 1968.[13] Construction efforts suffered many setbacks and the project went well over time and budget. One of the biggest setbacks was the discovery of fault lines in the path of the tunnel that were not discovered during the pilot bores,[26] these faults began to slip during construction and emergency measures had to be taken to protect the tunnels and workers from cave-ins and collapses.[22] A total of nine workers were killed during the construction of both bores. Further complicating construction was that the boring machines could not work as fast as expected at such high altitudes, and the productivity was significantly less than planned, the frustration prompted one engineer to comment, "We were going by the book, but the damned mountain couldn't read".[26] The first bore was dedicated March 8, 1973. Initially this tunnel was used for two-way traffic, with one lane for each direction, the amount of traffic through the tunnel exceeded predictions, and efforts soon began to expedite construction on the second tube (the Johnson bore), which was finished on December 21, 1979.[13] The initial engineering cost estimate for the Eisenhower bore was $42 million; the actual cost was $108 million (equivalent to $595 million today). Approximately 90% of the funds were paid by the federal government, with the state of Colorado paying the rest, at the time, this figure set a record for the most expensive federally aided project. The excavation cost for the Johnson bore was $102.8 million (equivalent to $347 million today).[26][27]

A parking lot with a view of several snow-capped mountains
Rest area along I-70 at the top of Vail Pass

The tunnel construction became unintentionally involved in the women's rights movement when Janet Bonnema was accepted for an engineering technician position in the construction of the Straight Creek Tunnel in 1970. Bonnema was restricted from entering the tunnel itself, however, due to the miners' superstition that women who entered underground mines and tunnels would bring bad luck; in 1972 Bonnema filed a $100,000 class action suit against the Colorado Department of Transportation, citing Title VII of the Civil Rights Act of 1964. As Colorado voters had passed the Equal Rights Amendment that year, the state settled Bonnema's case out of court for $6,730. Bonnema entered the tunnel for the first time on November 9, 1972, prompting 66 workers to temporarily walk off the job; most returned the next day. She continued with the project until the tunnel opened.[28]

Vail Pass[edit]

While designing the Eisenhower Tunnel, controversies erupted over how to build the portions over Vail Pass and Glenwood Canyon, the route of US 6 over Vail Pass has a distinctive "V" shape. Initially engineers thought they could shorten the route of I-70 by about 10 miles (16 km) by tunneling from Gore Creek to South Willow Creek, an alternative known as the Red Buffalo Tunnel.[22] This alternative sparked a nationwide controversy as it would require an easement across federally protected lands, through what is now called the Eagles Nest Wilderness, after the U.S. Secretary of Agriculture refused to grant the easement, the engineers agreed to follow the existing route across Vail Pass. The engineers added infrastructure to accommodate wildlife, and had significant portions of the viaducts constructed offsite and lifted in place to minimize the environmental footprint,[22] the grade over Vail Pass reaches seven percent.[29]

Glenwood Canyon[edit]

A two tiered highway snaking around bends in a canyon, with some fall foliage visible
I-70 in Glenwood Canyon as seen from the California Zephyr

Glenwood Canyon has served as the primary transportation artery through the Rocky Mountains, even before the creation of U.S. highways. Railroads have used the canyon since 1887 and a dirt road was built through the canyon in the early 20th century,[8] the first paved road was built from 1936 to 1938 at a cost of $1.5 million (equivalent to $26 million today).[22]

With the Eisenhower Tunnel finished, the last remaining obstacle for I-70 to be an interstate commercial artery was the two lane, non-freeway portion in Glenwood Canyon. Construction had started on this section in the 1960s with a small section opening to traffic in 1966,[4] the remainder was stopped due to environmentalist protests that caused a 30-year controversy.[12] The original design was criticized as "the epitome of environmental insensitivity". Engineers scrapped the original plans and started work on a new design that would minimize additional environmental impacts.[30] A new design was underway by 1971, which was approved in 1975; however, environmental groups filed lawsuits to stop construction, and the controversy continued even when construction finally resumed in 1981.[22] The final design included 40 bridges and viaducts, three additional tunnel bores (two were completed before construction was stopped in the 1960s) and 15 miles (24 km) of retaining walls for a stretch of freeway 12 miles (19 km) long.[6] The project was further complicated by the need to build the four-lane freeway without disturbing the operations of the railroad, this required using special and coordinated blasting techniques.[31] Engineers designed two separate tracks for the highway, one elevated above the other, to minimize the footprint in the canyon,[8] the final design was praised for its environmental sensitivity. A Denver architect who helped design the freeway proclaimed, "Most of the people in western Colorado see it as having preserved the canyon." He further stated, "I think pieces of the highway elevate to the standard of public art."[30] A portion of the project included shoring up the banks of the Colorado River to repair damage and remove flow restrictions created in the initial construction of US 6 in the 1930s.[32]

Diagram showing the former profile of a canyon wall with a new profile showing re-graded slopes, re-graded riverbank, medians and a two-tiered highway. The tops of the highway cantilever over the retaining wall, to hide the infrastructure below.
Department of Transportation drawing showing how re-using the existing footprint of US 6 combined with elevating two lanes helped minimize the environmental impact of the freeway on Glenwood Canyon

The freeway was finally completed on October 14, 1992, in a ceremony covered nationwide.[33][34] Most coverage celebrated the engineering achievement or noted this was the last major piece of the Interstate Highway System to open to traffic. However, newspapers in western Colorado celebrated the end of the frustrating traffic delays, for most of the final 10 years of construction, only a single lane of traffic that reversed direction every 30 minutes remained open in the canyon. One newspaper proudly proclaimed "You heard right, for the first time in more than 10 years, construction delays along that 12-mile (19 km) stretch of Interstate 70 will be non-existent."[35]

The cost was $490 million (equivalent to $900 million today) to build 12 miles (19 km), 40 times the average cost per mile predicted by the planners of the Interstate Highway system.[22] This figure exceeded that of Interstate 15 through the Virgin River Gorge, which was previously proclaimed the most expensive rural freeway in the United States,[36] the construction of I-70 through Glenwood Canyon earned 30 awards for the Colorado Department of Transportation,[8] including the 1993 Outstanding Civil Engineering Achievement Award from the American Society of Civil Engineers.[37] At the dedication it was claimed that I-70 through Glenwood Canyon was the final piece of the Interstate Highway System to open to traffic, for this reason, the system was proclaimed to be complete.[6][8] However, as of 2017, at least two sections of the original Interstate Highway System have not been constructed: a section of Interstate 95 in central New Jersey,[38] and a section of I-70 in Breezewood, Pennsylvania.[39]


When first approved, the extension of I-70 from Denver to Cove Fort was criticized in some area newspapers as a road to nowhere;[40] an information liaison specialist with the U.S. Department of Transportation in Baltimore, Maryland—the eastern terminus of I-70—claims people have asked "did we think Baltimoreans were so desperate to get to Cove Fort that we were willing to pay $4 billion to get them there?"[12] However, a resident engineer with the USDOT has called the extension one of the "crown jewels" of the Interstate Highway System;[8] in Colorado, the freeway helped unite the state, despite the two halves being separated by the formidable Rocky Mountains. The Eisenhower Tunnel alone is credited with saving up to an hour from the drive across the state.[22] Prior to I-70's construction, the highway through Glenwood Canyon was one of the most dangerous in the state, with the improvements, the accident rate has dropped 40% even though traffic through the canyon has substantially increased.[8] The Colorado Department of Transportation is considering the nomination of various portions of I-70 as a National Historic Landmark, even though the freeway will not qualify as historical for several decades.[22]

I-70 through the Colorado Plateau

The freeway is credited with enhancing Colorado's ski industry, the ski resort town of Vail did not exist until I-70 began construction, with developers working in close partnership with the Department of Transportation.[22] By 1984, the I-70 corridor between Denver and Grand Junction contained the largest concentration of ski resorts in the United States, the towns and cities along the corridor have experienced significant growth, luring recreational visitors from the Denver area. As one conservationist lamented, I-70 "changed rural Colorado into non-rural Colorado".[22]

One accident at the Mousetrap, a complex interchange, had national ramifications, on August 1, 1984, a truck carrying six torpedoes for the U.S. Navy overturned. The situation was made worse as no one answered at the phone number provided with the cargo, and an unknown liquid was leaking from one of the torpedoes, it took more than three hours before any military personnel arrived on the scene, U.S. Army personnel from a nearby base. The incident left thousands of cars stranded and Denver's transportation network paralyzed for about eight hours. Approximately 50 residents in the area were evacuated.[41][42] Investigations later revealed that the truck driver did not follow a recommended route provided by state troopers, who specifically warned the driver to avoid the Mousetrap,[41] the Navy promised reforms after being criticized for providing an unstaffed phone number with a hazardous cargo shipment, a violation of federal law, and failing to notify Denver officials about the shipment.[43][44] The Mousetrap was grandfathered into the Interstate Highway system, with some structures built in 1951,[4] the incident provided momentum to rebuild the interchange with a more modern and safer design. Construction began in several phases in 1987 and the last bridge was dedicated in 2003.[45]

In 2014, mile marker 420 was altered by CDOT to read "Mile 419.99" following repeat thefts of the original sign due to the significance of the number 420 in cannabis culture.[46]


CDOT plans to rebuild the 1.8-mile (2.9 km) elevated section of I-70 between Brighton Boulevard and Colorado Boulevard in Denver as a below-grade highway and widen other sections between I-25 and Chambers Road in Aurora, beginning construction in 2018. The $1.2 billion project, financed through a public–private partnership with Kiewit and Meridiam, would add a new express toll lane and build frontage roads; the below-grade freeway would have a four-acre (1.6 ha) park built over the top between Clayton and Columbine streets.[47] The project has attracted controversy from activists opposed to highway expansion, including lawsuits filed over changes to federal air quality standards that would allow the project to be built.[48][49]

Exit list[edit]

County Location[50] mi[50] km Exit Destinations Notes
Mesa 0.000 0.000 I-70 west / US-6 west / US-50 west – Green River Continuation into Utah
1.814 2.919 2 Rabbit Valley
11.106 17.873 11 US 6 east / US 50 east – Mack Eastern end of concurrency with US 6/US 50
15.081 24.271 15 SH 139 north – Loma, Rangely
Fruita 19.444 31.292 19 US 6 / SH 340 – Fruita
Grand Junction 25.563 41.140 26 I-70 Bus. east / US 6 / US 50 – Grand Junction Grand Junction only appears on eastbound signage
27.570 44.370 28 24 Road/Redlands Parkway
31.351 50.455 31 Horizon Drive
36.644 58.973 37 I-70 Bus. west to US 6 – Clifton, Delta, Grand Junction Delta only appears on eastbound signage; US 6 and Grand Junction only appear on westbound signage
41.578 66.913 42 To US 6 – Palisade US 6 only appears on eastbound signage
43.682 70.299 44 US 6 west – Palisade Westbound exit and eastbound entrance; western end of concurrency with US 6
45.332 72.955 46 Cameo
46.867 75.425 47 James M. Robb – Colorado River State Park, Island Acres Former port of entry
49.015 78.882 49 SH 65 south to SH 330 east – Grand Mesa, Collbran
50.381 81.080 Beavertail Tunnel
61.648 99.213 62 De Beque
Garfield 72.230 116.243 72 US 6 to CR 215 north – West Parachute Opened October 31, 2012[51]
Parachute 74.661 120.155 75 Parachute, Battlement Mesa
81.236 130.737 81 Rulison
86.850 139.772 87 US 6 east – Rifle Eastern end of concurrency with US 6
Rifle 90.422 145.520 90 SH 13 north – Rifle, Meeker
93.991 151.264 94 Garfield County Regional Airport
Silt 97.427 156.794 97 I-70 Bus. north – Silt
105.260 169.400 105 New Castle
109.000 175.418 109 Canyon Creek
111.328 179.165 111 South Canyon
Glenwood Springs 114.295 183.940 114 West Glenwood
116.380 187.295 116 SH 82 – Glenwood Springs, Aspen
118.640 190.933 119 No Name
120.954 194.657 121 Grizzly Creek to Hanging Lake Hanging Lake only appears on westbound signage
122.660 197.402 123 Shoshone Eastbound exit and westbound entrance
125.061 201.266 125 Hanging Lake Eastbound exit and westbound entrance
125.269 201.601 Hanging Lake Tunnel
128.317 206.506 129 Bair Ranch
Eagle 133.384–
133 Dotsero
Gypsum 139.533 224.557 140 US 6 east – Gypsum Eastern end of concurrency with US 6
Eagle 146.648 236.007 147 Eagle
156.547 251.938 157 SH 131 north – Wolcott, Steamboat Springs
162.782 261.972 163 I-70 Bus. south – Edwards
Avon 166.635 268.173 167 Avon
168.157 270.622 168 William J. Post Boulevard – Avon East Entrance
168.758 271.590 169 US 6 – Eagle-Vail Westbound exit and eastbound entrance
171.105 275.367 171 US 6 west / US 24 east – Minturn, Leadville Western end of concurrency with US 6
Vail 173.319 278.930 173 West Vail
176.057 283.336 176 Vail Town Center
179.866 289.466 180 East Vail
Summit 190.095 305.928 190 Rest area Vail Pass
195.298 314.302 195 SH 91 south – Copper Mountain, Leadville
197.854 318.415 198 Officers Gulch
200.995 323.470 201 Main Street – Frisco, Breckenridge Breckenridge only appears on eastbound signage; Main Street only appears on westbound signage
202.352 325.654 203 SH 9 south – Frisco, Breckenridge Western end of concurrency with SH 9; Breckenridge only appears on westbound signage
Silverthorne 205.423 330.596 205 US 6 east / SH 9 north – Silverthorne, Dillon Eastern end of concurrency with US 6/SH 9
SummitClear Creek
county line
Eisenhower Tunnel
Clear Creek 216.185 347.916 216 US 6 west – Loveland Pass Western end of concurrency with US 6
218.346 351.394 218 (no name) Connects to Herman Gulch Road[52]
221.297 356.143 221 Bakerville
Silver Plume 225.719 363.260 226 Silver Plume
Georgetown 227.910 366.786 228 Georgetown
231.889 373.189 232 US 40 west – Empire, Granby Western end of concurrency with US 40
233.047 375.053 233 Lawson Eastbound exit only
234.209 376.923 234 Downieville, Dumont, Lawson Dumont only appears on eastbound signage; Lawson only appears on westbound signage
235.005 378.204 235 Dumont Westbound exit and eastbound entrance
237.660 382.477 238 Fall River Road
Idaho Springs 238.704–
239 I-70 Bus. east – Idaho Springs No eastbound entrance; I-70 Bus. only appears on eastbound signage
239.652 385.683 240 SH 103 – Mount Evans
241.125 388.053 241 I-70 Bus. west – Idaho Springs I-70 Bus. only appears on westbound signage
242.292 389.931 Veterans Memorial Tunnels[14]
242.980 391.038 243 Hidden Valley, Central City
244.260 393.098 244 US 6 east / US 40 east – Golden Left exit eastbound; left entrance westbound; no eastbound entrance; eastern end of concurrency with US 6/US 40
246.602 396.867 247 Beaver Brook, Floyd Hill Eastbound exit and westbound entrance
Jefferson 247.604 398.480 248 Beaver Brook, Floyd Hill Westbound exit and eastbound entrance
250.769 403.574 251 El Rancho Eastbound exit and westbound entrance
251.318 404.457 252 SH 74 (Evergreen Parkway) / US 40 west Westbound exit and eastbound entrance; western end of concurrency with US 40
252.244 405.947 253 Chief Hosa
253.528 408.014 254 US 40 east – Genesee Park Eastern end of concurrency with US 40
255.974 411.950 256 Lookout Mountain
258.722 416.373 259 US 40 east – Golden, Morrison Eastbound signage
CR 93 – Morrison Westbound signage
Golden 259.803 418.112 260 US 6 west (6th Avenue) / SH 470 east – Colorado Springs US 6 only appears on eastbound signage; no westbound exit to US 6; no eastbound entrance from US 6
261.030 420.087 261 US 6 east (6th Avenue) Eastbound exit and westbound entrance
261.630 421.053 262 US 40 / I-70 Bus. (Colfax Avenue) to US 6 I-70 Bus. only appears on eastbound signage; US 6 only appears on westbound sigange
Lakewood 262.571 422.567 263 Colorado Mills Parkway – Denver West
Wheat Ridge 264.341 425.416 264 Youngfield Street/32nd Avenue
265.343 427.028 265 SH 58 west – Golden, Central City
265.726 427.645 266 SH 72 (Ward Road) / 44th Avenue
267.402 430.342 267 SH 391 (Kipling Street)
Arvada 269.005 432.922 269A SH 121 (Wadsworth Boulevard)
269.242 433.303 269B I-76 east – Fort Morgan Eastbound left exit and westbound entrance; western terminus of I-76
Wheat RidgeLakeside line 270.000 434.523 270 SH 95 (Sheridan Boulevard) / Harlan Street Eastbound signage
Harlan Street Westbound signage
county line
LakesideDenver line 270.496 435.321 271A SH 95 (Sheridan Boulevard) Westbound exit and eastbound entrance
City and County of Denver 271.549 437.016 271B Lowell Boulevard/Tennyson Street Westbound exit and eastbound entrance
272.005 437.750 272 US 287 (Federal Boulevard)
273.015 439.375 273 Pecos Street
274.062 441.060 274 I-25 – Fort Collins, Colorado Springs The Mousetrap; western end of concurrency with US 6/US 85; exit 214A on I-25
274.607 441.937 275A Washington Street Unnumbered and part of exit 274 eastbound
275.252 442.975 275B SH 265 north (Brighton Boulevard)
275.545 443.447 275C York Street/Josephine Street Eastbound exit and westbound entrance
276.080 444.308 276A US 6 east / US 85 north (Vasquez Boulevard) Eastbound signage; eastern end of concurrency with US 6/US 85
Steele Street/Vasquez Boulevard Westbound signage
276.572 445.099 276B SH 2 (Colorado Boulevard) to US 6 east / US 85 north US 6 and US 85 only appear on westbound signage
277 Dahlia Street/Holly Street/Monaco Street
278.548 448.280 278 SH 35 (Northfield Quebec Street)
279.086 449.145 279A I-270 west / US 36 west – Fort Collins, Boulder Westbound exit and eastbound entrance; western end of concurrency with US 36
279.591 449.958 279B Central Park Boulevard
280.567 451.529 280 Havana Street
281.560 453.127 281 Peoria Street Unnumbered and part of Exit 282 westbound
county line
DenverAurora line 282.271–
282 I-225 south – Aurora, Colorado Springs Exit 12 on I-225
Adams Aurora 283.532 456.301 283 Chambers Road
283.623 456.447 284 Peña Boulevard – Denver International Airport Eastbound exit and westbound entrance
284.627 458.063 285 Airport Boulevard
285.727 459.833 286 Tower Road
288.219 463.844 288 I-70 Bus. / US 40 west / US 287 north (Colfax Avenue) Left exit westbound; no westbound entrance; I-70 Bus. only appears on westbound signage; western end of concurrency with US 40/US 287
289.028 465.145 289 E-470 – Fort Collins, Colorado Springs Exit 20 on E-470
292.128 470.134 292 SH 36 east (Airpark Road)
295.256 475.168 295 I-70 Bus. north – Watkins
299.328 481.722 299 Manila Road
304.360 489.820 304 SH 79 north – Bennett
305.259 491.267 305 Kiowa Eastbound exit only
Arapahoe 305.784 492.112 306 Rest area Eastbound signage
Kiowa, Bennett Westbound signage; no eastbound entrance
310.165 499.162 310 I-70 Bus. north – Strasburg
315.913 508.413 316 US 36 east – Byers Eastern end of concurrency with US 36
322.086 518.347 322 Peoria
Deer Trail 328.329 528.394 328 I-70 Bus. south – Deer Trail
Elbert 336.787 542.006 336 Lowland
340.354 547.747 340 I-70 Bus. west – Agate
348.731 561.228 348 Cedar Point
352.340 567.036 352 SH 86 west – Kiowa
354.537 570.572 354 (no name)
Lincoln Limon 359.499 578.558 359 I-70 Bus. east to US 24 / SH 71 – Limon Eastbound signage
US 24 – Colorado Springs Westbound signage
361.743 582.169 361 I-70 Bus. to SH 71 – Limon SH 71 only appears on eastbound signage
363.025 584.232 363 US 40 east / US 287 south – Hugo, Kit Carson Eastbound signage; eastern end of concurrency with US 40/US 287
I-70 Bus. / US 24 west to SH 71 – Limon Westbound signage; western end of concurrency with US 24
371.482 597.842 371 Genoa, Hugo Hugo only appears on westbound signage
376.520 605.950 376 Bovina
Arriba 383.496 617.177 383 Arriba
Kit Carson 394.564 634.989 395 Flagler
405.065 651.889 405 US 24 east / SH 59 – Seibert Eastern end of concurrency with US 24
411.961 662.987 412 Vona
419.311 674.816 419 SH 57 – Stratton
428.824 690.125 429 Bethune
436.788 702.942 437 I-70 Bus. / US 385 (Lincoln Street) I-70 Bus. only appears on eastbound signage
Burlington 438.225 705.255 438 I-70 Bus. / US 24 (Rose Avenue) I-70 Bus. only appears on westbound signage; western end of concurrency with US 24
449.589 723.543 I-70 east / US-24 east Continuation into Kansas
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also[edit]


  1. ^ a b c Colorado Department of Transportation. "Highway Data". Colorado Department of Transportation. Archived from the original on May 26, 2012. Retrieved February 16, 2008. 
  2. ^ a b c d e f g h i j DeLorme (2002). Colorado Atlas & Gazetteer (Map) (2002 ed.). 1 in:2.5 mi. Yarmouth, ME: DeLorme. ISBN 0-89933-288-9. OCLC 52156345. 
  3. ^ Grand Junction Visitor & Convention Bureau. "Grand Junction Colorado: Trip Planning". Grand Junction Visitor & Convention Bureau. Archived from the original on February 6, 2009. Retrieved February 22, 2009. 
  4. ^ a b c d e f g h Colorado Department of Transportation. "The History of I-70 in Colorado". Colorado Department of Transportation. Retrieved April 1, 2008. 
  5. ^ a b Weingroff, Richard F. (Summer 1996). "Dwight D. Eisenhower System of Interstate and Defense Highways Engineering Marvels". Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved February 15, 2008. 
  6. ^ a b c d Colorado Department of Transportation. "CDOT Fun Facts". Colorado Department of Transportation. Retrieved March 27, 2015. 
  7. ^ Flat Iron Construction Company. "Glenwood Canyon Corridor". Flat Iron Construction Company. Retrieved April 20, 2009. 
  8. ^ a b c d e f g Stufflebeam Row, Karen; LaDow, Eva; Moler, Steve (March–April 2004). "Glenwood Canyon 12 Years Later". Public Roads. Washington, DC: Federal Highway Administration. 67 (5). Retrieved August 9, 2009. 
  9. ^ Federal Highway Administration (October 22, 2008). "Bicycle and Pedestrian Guidance". Federal Highway Administration. Retrieved April 30, 2008. 
  10. ^ Zimmermann, Karl (2004). Burlington's Zephyrs. Saint Paul, MN: MBI Publishing Company. pp. 38–40. ISBN 978-0-7603-1856-0. 
  11. ^ Buena Vista Chamber of Commerce (April 29, 2009). "Collegiate Peaks Scenic Byway/Highway of the Fourteeners". Buena Vista Chamber of Commerce. Archived from the original on October 30, 2010. Retrieved June 13, 2009. 
  12. ^ a b c d e f g h Weingroff, Richard (December 29, 2008). "Why Does I-70 End in Cove Fort, Utah?". Ask the Rambler. Federal Highway Administration. Retrieved June 7, 2009. 
  13. ^ a b c d e f Colorado Department of Transportation. "Eisenhower Tunnel". Colorado Department of Transportation. Retrieved June 15, 2009. 
  14. ^ a b Colorado Department of Transportation (December 11, 2014). "Work to Realign I-70 Traffic Through Veterans Memorial Tunnel Scheduled to Begin Saturday Evening" (Press release). Colorado Department of Transportation. Retrieved February 17, 2015. 
  15. ^ Colorado Department of Transportation. "Structure List for Highway 070". Colorado Department of Transportation. Archived from the original on May 26, 2012. Retrieved July 1, 2011. 
  16. ^ National Park Service (July 19, 2007). "Rocky Mountain National Park: The Dakota Hogback". National Park Service. Retrieved July 21, 2009. 
  17. ^ Federal Highway Administration (2009). US 36 Corridor Project, Denver, Colorado Metropolitan Area: Environmental Impact Statement. Federal Highway Administration. p. 402 – via Google Books. 
  18. ^ Colorado Department of Transportation. "Straight Line Diagram (for I-70)". Colorado Department of Transportation. Archived from the original on September 8, 2009. Retrieved September 21, 2009. 
  19. ^ "A Need for Speed(ways): Colorado's Long and Winding Road Before Joining Eisenhower's Interstate Plan". Rocky Mountain News. June 29, 2006. Archived from the original on July 17, 2011. Retrieved June 13, 2009. 
  20. ^ Colorado Tourism Office. "Lets Talk Colorado: Limon". Colorado Tourism Office. Retrieved July 23, 2009. 
  21. ^ Colorado Tourism Office. "Lets Talk Colorado: Driving to Colorado from the Kansas State Line: I-70 and Hwy. 50 West". Colorado Tourism Office. Retrieved July 23, 2009. 
  22. ^ a b c d e f g h i j k l m n o p q Associated Cultural Resource Experts (2002). Highways to the Sky: A Context and History to Colorado's Highway System. Colorado Department of Transportation. Retrieved May 22, 2009. 
  23. ^ Noeth, Louise Ann (2002). Bonneville: The Fastest Place on Earth. St. Paul, MN: MotorBooks/MBI Publishing Company. p. 18. ISBN 0-7603-1372-5. OCLC 50514045. Retrieved August 9, 2009 – via Google Books. 
  24. ^ Weingroff, Richard F. (January 1, 2009). "U.S. 6: The Grand Army of the Republic Highway". Highway History. Federal Highway Administration. Retrieved May 24, 2009. 
  25. ^ Rand McNally (1946). "Southwest (Colorado, New Mexico)" (Map). Road Atlas. Scale not given. Chicago: Rand McNally. p. 24. Retrieved May 5, 2008 – via Broer Map Library. 
  26. ^ a b c Colorado Department of Transportation. "Eisenhower Memorial Bore". Colorado Department of Transportation. Retrieved July 25, 2009. 
  27. ^ Colorado Department of Transportation. "Edwin C Johnson Bore". Colorado Department of Transportation. Retrieved July 25, 2009. 
  28. ^ Howard, Jane (December 8, 1972). "Janet Fights the Battle of Straight Creek Tunnel". Life. pp. 49–52. Retrieved June 7, 2017 – via Google Boosk. 
  29. ^ Colorado Department of Transportation. "Maximum Grades on Colorado Mountain Passes". Colorado Department of Transportation. Retrieved January 8, 2016. 
  30. ^ a b Garner, Joe (August 31, 1999). "Freeway Opened the State to the Rest of the U.S." Rocky Mountain News. [permanent dead link]
  31. ^ Scotese, Thomas; Ackerman, John (1992). "Engineering Considerations for the Hanging Lake Tunnel Project, Glenwood Springs, Colorado" (PDF). International Society of Explosives Engineers. Archived from the original (PDF) on February 10, 2005. Retrieved April 30, 2009. 
  32. ^ McGregor, Heather (May 22, 1994). "Old Tires to Heal Glenwood Scar: Highway Eyesore Dates to 1930s". The Denver Post. p. C7. 
  33. ^ "Travel Advisory; New I-70 Stretch Helps Skiers". The New York Times. November 1, 1992. Retrieved September 8, 2009. 
  34. ^ "Nation Briefings". Chicago Sun-Times. October 15, 1992. 
  35. ^ Williams, Leroy (June 8, 1993). "Glenwood Canyon Traffic Can Savor Delay-Free Season". Rocky Mountain News. [page needed]
  36. ^ "Costliest Rural Freeway: $100 an Inch". Fresno Bee. November 26, 1972. [page needed]
  37. ^ American Society of Civil Engineers. "Outstanding Civil Engineering Achievement Award". American Society of Civil Engineers. Archived from the original on May 9, 2008. Retrieved February 24, 2008. 
  38. ^ Edwards & Kelsey. "I-95/I-276 Interchange Project Meeting Design Management Summary—Draft: Design Advisory Committee Meeting #2" (PDF). Pennsylvania Turnpike Commission. Retrieved August 3, 2009. 
  39. ^ Weingroff, Richard. "Why Does The Interstate System Include Toll Facilities?". Ask The Rambler. Federal Highway Administration. 
  40. ^ Geary, Edward A. "Interstate 70". Utah History to Go. State of Utah. Retrieved February 16, 2008. 
  41. ^ a b "Army Rights Tipped Truck Carrying Navy Torpedoes". The Spokesman-Review. Spokane, WA. Associated Press. August 2, 1984. p. 10. Retrieved September 24, 2009 – via Google News. 
  42. ^ Getlin, Josh (September 20, 1987). "Record of Risk-Free Transportation Torpedoed by Denver's Experience". Los Angeles Times. p. 26. Retrieved September 24, 2009. 
  43. ^ "Errors Many in Torpedo Incident". Eugene Register-Guard. August 10, 1984. p. 14A – via Google News. 
  44. ^ Kowalski, Robert (February 26, 1990). "Hazardous Cargo at Heart of Controversy". The Denver Post. [page needed]
  45. ^ Flynn, Kevin (December 16, 2003). "This Mousetrap Wasn't a Snap". The Denver Post. [page needed]
  46. ^ Leasca, Stacy (January 13, 2014). "Colorado Replaces Marker 420 with 419.99 to Foil 'Weed Enthusiasts". Los Angeles Times. Retrieved April 21, 2015. 
  47. ^ Colorado Department of Transportation (February 2017). "Central 70 Project Snapshot" (PDF). Colorado Department of Transportation. Retrieved September 26, 2017. 
  48. ^ Murray, Jon (April 17, 2017). "Activism, Lawsuits Could Delay or Derail the Massive I-70 Expansion in Denver—But Are They Long Shots?". The Denver Post. Retrieved September 26, 2017. 
  49. ^ Paul, Jesse (August 24, 2017). "CDOT picks Kiewit Meridiam Partners to lead $1.2 billion I-70 expansion, as project's controversy simmers". The Denver Post. Retrieved September 26, 2017. 
  50. ^ a b Colorado Department of Transportation. "Highway Data Explorer, Online Transportation Information System". Colorado Department of Transportation. Archived from the original on September 10, 2012. Retrieved September 8, 2016. 
  51. ^ Lott, Renelle (October 31, 2012). "Ribbon Cutting Marks Upcoming November Opening of new I-70 West Parachute Interchange" (Press release). Garfield County, Colorado. Retrieved February 27, 2013. 
  52. ^ Colorado Department of Transportation. "Highway Data Explorer". Online Transportation Information System. Colorado Department of Transportation. Archived from the original on September 10, 2012. Retrieved August 31, 2017. 

External links[edit]

Route map: Google

KML is from Wikidata

Interstate 70
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