Interstate 25 History

Overview

I-25 construction was finished in Colorado on Sept. 21, 1969, with the opening of a 21-mile segment south of Walsenburg ( Rugby area). Total length of I-25 in CO: 299 miles

Cost: $125 million

Segment	Location/Description	Completion
Denver	11.2 miles, Valley Highway	48 th Ave. to Evans, Fully opened 1958
Pueblo	9.2 miles through Pueblo	Opened July 1, 1959
Colorado Spgs.	12 miles through the city	Opened July 1, 1960
South of Pueblo to Monument	67 miles, south of Pueblo to north of Colorado Springs	Opened by 1961
Denver Northside	N. end of Valley to 58 th , .5 miles	Opened in 1961
Longmont Area	SH 7 to SH 66, 14 miles	Opened in 1961
Trinidad	Elevated portion, approx. 3 mi.	Completed in 1963
Castle Rock to Denver	Approximately 25 miles	Completed in 1963
Denver north	58 th Ave. to SH 7, 14 miles	Completed in 1963
North of Denver	SH 66 to U.S. 34, 14 miles	Completed in 1963
Walsenburg	Walsenburg Bypass	Completed in 1964
North Link	17 miles, N of Wellington ( Buckeye Road ) to Border	Completed Oct. 11, 1966
Colorado City	SH 165 to Pueblo Blvd. , 20 miles	Completed in 1965
Monument Hill	Monument to Larkspur, 12 miles	Completed in 1965
Ft. Collins Area	U.S. 34 to SH 68 (Harmony), 8 mi.	Completed in 1965
Trinidad/Raton Pass	S. edge of Trinidad to Raton Pass at New Mexico Line – 13 mi.	Completed in 1966
Walsenburg to Colorado City	22 miles	Completed in 1968
Larkspur to Castle Rock	9 miles	Completed in 1968
SH 68 to North of Wellington	Harmony Rd. Ft. Collins to Buckeye Road , 23 miles	Completed in 1968; I-25 continuous from Walsenburg to Colorado/Wyoming border
Trinidad to Walsenburg	21 mile segment	Completed in 1969; I-25 in Colorado complete

Major Projects on I-25 from 1990 to 2005

I-25 Widening Safety Project, Lincoln Ave. to Castle Pines, Douglas County

Approval for the addition of a slow-vehicle climbing/descent lanes on the four-mile I-25 segment from Lincoln Avenue to Castle Pines North in Douglas County was received from Congress in November, 1997. Project cost: $19.7 million. Began: July, 1998. Completion: 2000. Planning for the improvements was already underway when, in February of 1997, 82 vehicles were involved in accidents during a “routine” snowstorm on I-25 at Surrey Ridge. Two dozen people were injured and the freeway was closed for 10 hours.

I-25 Mousetrap/North Improvements Program, Denver

This multi-year program was planned after the torpedo incident in the Mousetrap (intersection of I-25 & I-70 northwest of downtown Denver ) on August 1, 1984.

In 1987, the 44 th Ave. , bridge over I-25 was replaced and I-25 beneath was widened to accommodate future HOV lanes. In 1989, construction of the new I-70 bridges over I-25 began. These bridges were completed and the ribbon cutting was held Dec. 27, 1991.

Improvements on I-25 in the area from 20 th Avenue north to 70 th Avenue continued largely unabated from 1987 until 1995. The freeway was widened, accesses were improved, and two high occupancy vehicle (HOV) lanes were built in the center of the freeway between 20 th Avenue near downtown to the 70 th Avenue bridge. The HOV lanes were open to southbound vehicles with two or more passengers in the morning hours, and northbound in the afternoon rush hours. The lanes were also used to help heavy traffic rushes out of central Denver after large special events are held, such as Bronco football games at Invesco Field at Mile High.

Other major I-25 improvements in the area included the Park Avenue Flyover (see below), improved ramps between I-25 and I-70, reconstruction, widening, and realignment north of I-70 on I-25, and work in the intersections of I-25 & U.S. 36, and I-25 & I-270. The completion of HOV lanes north to 58 th Ave. occurred in 1995; the lanes were later extended on to 70 th Avenue as well as to U.S. 36 to the vicinity of the Sheridan Blvd. interchange.

T-REX, Denver

The T-REX project, the largest multi-modal transportation project in Colorado history, began in September, 2001, and will conclude in November, 2006, two years ahead of its initial completion target date. The $1.67 billion project will widen and install safety improvements along 19 miles of I-25 and I-225 in Denver , will add 19.7 miles of light rail line, and will rebuild eight interchanges. The format is design-build, meaning that the project is being designed as it is being built. Public perception of project progress has been favorable. Few problems other than ever-growing traffic volumes on the corridor have been noted during the construction period.

Park Avenue Flyover Ramp, Denver

Precast concrete girders 121 feet in length and weighing 400,000 pounds, heavier than five loaded semi-trucks, highlighted the flyover ramp dubbed as the “Gateway to Downtown Denver.” The purpose of the ramp was to streamline commuter traffic into the downtown area, especially by allowing eastbound and westbound traffic on I-70 to have a direct link to it and bypassing I-25 completely. Other features of the project which completed the mousetrap and north I-25 improvements included additional through-lanes on I-25 both north and southbound, improved access to the freeways from Park Avenue westbound commuter traffic, and reconstruction of Globeville Road . The total cast was $48 million. Dedication was held on November 30, 1998.

Wolfensberger Interchange Improvements,
I-25 in Castle Rock

Ground was broken on May 23, 1995, for improvements at a major interchange in Castle Rock along I-25. Total cost: $2.8 million. A new four-lane bridge was built over I-25, ramps were improved, and left turn lanes from Wolfensberger to I-25 were added, eliminating the long traffic backups that had plagued the area. The project is notable because the Plum Creek area beneath the bridges was found to be habitat of the endangered Preble's Meadow Jumping Mouse. Environmental protection of this habitat and mitigation of loss of nearby wetlands brought much positive recognition to CDOT's environmental banking program. The project was completed in December, 1995.

COSMIX, Colorado Springs

Colorado Governor Bill Owens officially broke ground on the Colorado Springs Metro Interstate Expansion (COSMIX), a 2.5-year, $150 million program to increase I-25 capacity through the north side of Colorado Springs by widening the freeway to three lanes in each direction from Circle Drive to North Academy Boulevard and reconstructing the Bijou Street and North Nevada/Rockrimmon Boulevard interchanges. COSMIX is the largest transportation project ever undertaken in the rapidly-growing Colorado Springs area. Governor Owens stated that when I-25 opened in Colorado Springs in 1960, the highway carried about 8,500 vehicles day. In 2005, as COSMIX was getting underway, the average daily vehicle count in the COSMIX project area was 100,000 vehicles per day. By 2020, that number was expected to rise to 170,000 vehicles per day.

North Forty Project, Southwestern Weld County

A major $73 million project to widen and improve seven miles of I-25 from State Highway 7 to Weld County Road 16 kicked off on Dec. 19, 2001, with remarks by Colorado Governor Bill Owens. The project, dubbed the “North Forty”, widened the freeway to three lanes in each direction, installed 12 foot shoulders, reconstructed the Erie and WCR 8 interchanges (a park-n-ride was installed at WCR 8), and rebuilt the east Frontage Road. The project was completed in October, 2004.

I-25 North Corridor Improvements, Colorado Springs

CDOT announced in August, 1992, that plans called for spending $80 million for improvements, including soundwalls, interchanges, safety projects, and the complete reconstruction of the road between Fillmore and Bijou streets, in the decade of 1995-2005.

There were seven phases in this project, which ran for more than a decade. The first project, which reconstruction the interchange serving the South Entrance of the U.S. Air Force Academy, North Academy Boulevard , and SH 83, begin in March, 1997, and was completed in Nov., 1997, seven months ahead of schedule.

Other major work included reconstructing the SH 105 interchange at Monument, reconstruction I-25 between Bijou Street and Fillmore, a distance of 2.5 miles; reconstruction of interchanges at Nevada/Tejon and Circle Drive/Lake Avenue; rebuilding the Fountain Creek Bridges on South Academy Blvd. near Ft. Carson, and the reconstruction of the Woodmen Road Interchange on the north side of Colorado Springs.

A unique feature of the multi-year program was installation of 1,000 noisewall barrier panels along the west side of I-25, beginning in January, 1998, as a part of the Bijou to Fillmore reconstruction. The panels featured art designs that recall important historical and natural features of the Pikes Peak Region.

The program concluded in May, 2005, with completion of the SH 105/Monument project a few miles north of Colorado Springs.

Total cost: $190

Owl Canyon I-25 North Project

This project was one of the Colorado Transportation Commission's 7 th Pot (28 strategic corridors in Colorado ) projects. The project started north of Wellington , CO at milepost 282 and ended at the Wyoming state line (milepost 299), a total distance of 17 miles.

This was an “A + B” design-build contractor; the prime contractor Castle Rock Construction partnered with design firm GMJM Inc. to win the contract. The $26.3 million contract was awarded in February, 1998.

Work on the southbound portion began in May, 1998, and was completed in the fall of 1998. Work was suspended over the winter of 1998/99 and resumed in April, 1999, on the northbound lanes. The northbound side was completed in October, 1999. The entire freeway was rebuilt in concrete. Other improvements included refurbishing bridge decks, installing new bridge rails and guard rails, flattening side slopes, installing new signs, and making drainage improvements. Final project acceptance, after final reseeding, was June 6, 2001.

Historical Construction Highlights

Denver Valley Highway

Constructed August, 1948 to November, 1958

First planning, 1944. Charles D. Vail, CDOH Chief Engineer, contracted with the Denver consulting firm Crocker & Ryan for a feasibility study. Study completed Dec. 22, 1944.

Valley Highway was envisioned to move traffic efficiently from Greeley to Colorado Springs , along the right of way of U.S. 85.

Begun in 1948

Length: 11.1 miles (from west 53 rd Ave. at Acoma St. the new Denver/Colorado Springs Highway, East Colorado Ave. at South Colorado Blvd.)

Cost: $30.57 million

($10.3 million ROW; $20.25 million construction)

Numerous contracts were awarded through the various segments

First contract: relocation of irrigation ditch and sewer

Cost: $284,000

Began: August, 1948

Contractor: Colorado Constructors, Inc.

First segment: 2.2 miles, north city limits to 48 th Ave. Cost: $2.22 million

Contractor: Northwestern Engineering Company, Denver

Began: Nov. 16, 1948 Construction took: two years

Final Contract: West 3 rd Avenue to Emerson Street Length: 2.8 miles

Cost: $1.48 million

Bids Opened: April 23, 1958

Completion, November 23, 1958

Freeway had 54 miles of two-lane highway construction, including ramps & service roads

62 bridges, 73 miles of drainage pipes

Lawrence/Larimer connection to the West Colfax viaduct of the Valley Highway was opened January 5, 1963

Cost: $1.7 million

Pueblo Freeway

Constructed: 1949 to July 1, 1959

Old State Route 1 was built between Denver and Pueblo around 1919. It was a huge improvement over the previous wagon trails, but the trip between the two cities (130 miles) took about eight hours in those days, with about 2.5 hours required from Pueblo to Colorado Springs

First paved (concrete) roadway from Colorado Springs to Pueblo was completed in 1930. It was 18' wide and was on U.S. 85/87. This reduced the travel time from Pueblo to Colorado Springs to one hour.

Pueblo Freeway

Length: 9.2 miles

Cost: $10.6 million ($2.9 million of that for right of way acquisition)

35 Bridges

Total of 23 miles of two-lane highway, including ramps and frontage roads

25.5 miles of drainage pipe, ranging in size from 6” to 84” in diameter

20 construction contracts were awarded

First Segment: 40 th St. to U.S. 50 intersection, 3.3 miles

Cost: $534,000

Most expensive feature: .6 mile long bridge over Arkansas River and railroad at West 4 th

Cost: $1.77 million

Colorado Springs Monument Valley Freeway

Constructed: November, 1955 to July 1, 1960

Length: 12 miles

Cost: $12.2 million ($3.46 million for right of way acquisition)

Pre-contracts totaling $2.3 million were awarded in late 1955

First segment: Nevada to Cimarron

Cost: $2.25 million

Contract awarded: Nov. 1, 1957

Entire project included 13 construction contracts total

39.5 miles of two-lane highway, including ramps and frontage roads

38 bridges

Colorado-Wyoming Link of I-25

Constructed July 31, 1962 to Oct. 11, 1964

Section built on roadway of wagon road dating to July 7, 1862

Route was first paved in 1936 in two separate projects, costing $17,621 for a distance of 21 miles

Four miles north of Wellington , CO , to Colorado/Wyoming Border ( Wyoming segment on to Cheyenne )

Opened: Oct. 11, 1964

Length: Colorado 17 mi.; Wyoming 9 mi.

Cost: $4.49 million ( Colorado section); $4.2 million (Wyoming Section)

Total Cost: $8.69 million

Contracts for grading, structures, and construction of the Colorado segment went to out of state contractors: Wilbur Christensen Const., Rapid City , SD ; Mott Construction, Centerville , IA ; and Western Contracting, Sioux City , IA.

Unique feature of this project: due to more use of automated equipment than on any previous Colorado highway project, a record was set of laying 9,354 linear feet of concrete pavement, eight inches thick and 24 feet wide, in one day.

Trinidad Segment of I-25

Major work was required in the city of Trinidad and on the most mountainous portion of I-25, the climb from Trinidad to Raton Pass , which gains about 1,800 in 13 miles. Surveys from the top of Raton Pass down to Trinidad had been conducted in 1959 and 1960; surveys of the new route of I-25 through Trinidad began in 1960, almost simultaneously with the beginning of construction of I-25 at the summit of Raton Pass. The first segment built from Raton Pass was 2.5 miles descending to the north; this was then extended for several more miles to Starkville in 1962. This highest portion of I-25 was largely built off the grade of the old U.S. 85/87, which followed closely the route of the old Wootton Toll Road . I-25 required new grades and new construction in most places.

Construction on the portion through Trinidad began in 1961. U.S. 85/87 followed a route through Trinidad via Linden Street to North Ave. , west to Arizona St. , down Arizona to Commercial, Commercial to Main, then on Main west to Country Club and on up to the south on what is now known as the Santa Fe Trail .

Construction of the current northbound elevated portion of I-25 through Trinidad began in 1962. The structure was approximately 2,000 feet long. Construction of this segment was completed and the entire route through Trinidad was opened to two-way traffic in 1963. The final segment connecting the south end of Trinidad to Starkville , 3.5 miles above to the south, was completed and opened in 1966. The final elevated portion of the freeway, today's southbound viaduct structure, was opened in 1968. At that point, four lanes of divided highway were open all the way through Trinidad .

Final Section of I-25, 21 Miles/Huerfano & Las Animas Counties

The final segment of I-25 to be built in Colorado , totaling 21 miles between Walsenburg and Trinidad, was dedicated on Sunday, Sept. 21, 1969, at the Rugby Rest Area, midway between Trinidad and Walsenburg.

The contracts for the final two projects, totaling 21 miles, were both let on July 3, 1968. Leone Construction of Trinidad won a bid of $1.628 million for 6.5 miles of two-laning south of Walsenburg, and Pioneer Construction won a $1.82 million contract for the 14.5 m iles between Santa Clara Creek add Ludlow . Of that 14.5 miles, 11 comprised two-laning. Stultz Construction won the contract for construction of the Rugby Rest Area.

Completion of the 21-mile segment meant that four lanes of I-25 were open from Wyoming to New Mexico , 299 miles total.

Dedication ceremonies were hosted jointly by the Walsenburg and Chambers of Commerce hosted the dedication ceremonies.

Major Incidents

I-25 Walnut Street Bridge Collapse

Walnut Street Viaduct over I-25 in Denver , under construction, collapsed during the early morning hours of Oct. 4, 1985, killing one construction worker and injuring four others. The new viaduct was being built to replace the old Larimer Street Viaduct.

Torpedoes in the Mousetrap

The Mousetrap, so dubbed by a radio reporter in the 1960s, is the intersection of I-25 and I-70 northwest of downtown Denver . It was so called because it supposedly looked like a mousetrap from the air, and because it was infamous for trapping vehicles within its network of sharply curving ramps.

In the early-morning hours of August 1, 1984, a truck carrying a load of torpedoes on I-25 exited onto one of the off-ramps and, apparently traveling and too high a speed, dumped the load under the various Mousetrap structures. The freeway was closed for miles in all directions for several hours. The result of this mishap was worldwide publicity, and the realization that the Mousetrap was inadequate to handle the estimated 300,000 vehicles daily.

In 1964, the portion of newly-designated (1957) I-70 from Colorado Boulevard west to I-25 was opened on an elevated structure above 46th Ave. A modified interchange at I-25 was built (this interchange had previously served 46th Ave. ). One year later, in 1965, the portion of I-70 going west from I-25 was opened. This portion was aligned with 48th Ave.

Following the “Torpedoes in the Mousetrap” incident in 1984, plans were made to reconstruct the Mousetrap and the portion of I-25 that was first to open in Denver in 1951. See Mousetrap/I-70 North program notes below). In 1987, the 44 th Ave. , bridge over I-25 was replaced and I-25 beneath was widened to accommodate future HOV lanes. In 1989, construction of the new I-70 bridges over I-25 began. These bridges were completed and the ribbon cutting was held Dec. 27, 1991.

Improvements on I-25 in the area from 20th Avenue north to 70th Avenue continued largely unabated from 1987 until 1995. The freeway was widened, accesses were improved, and two high occupancy vehicle (HOV) lanes were built in the center of the freeway between 20th Avenue near downtown to the 70th Avenue bridge. While other highway improvements opened as they were completed, the HOV lanes were open to southbound vehicles with two or more passengers in the morning hours, and northbound in the afternoon rush hours. The lanes were also used to help heavy traffic rushes out of central Denver after large special events are held, such as Bronco football games at Invesco Field at Mile High.

1995 – CDOT announced that for the first time in six years, there will be no traffic delays on I-25 in Denver due to construction. The completion of the HOV lanes from downtown north to 58th means there will be no major construction projects on I-25 in the metro area during the 1995 summer season.