The FreightWaves Classics series of articles on U.S. interstate highways continues with an overview of Interstate 25 (I-25). Previous articles on interstate highways 2-24 can be found on the FreightWaves.com website by clicking the “Search for” area at the top right of the homepage and then enter “FreightWaves Classics.”
Like other interstates that end in an odd number, I-25 is mainly a north-south highway. It serves as the primary highway through New Mexico, Colorado and Wyoming. Along its nearly 1,063-mile route are three state capitals (Santa Fe, New Mexico; Denver, Colorado; and Cheyenne, Wyoming). In addition, I-25 serves Albuquerque, which is New Mexico’s largest city, as well as Pueblo and Colorado Springs in central Colorado.
Moving north, I-25 begins at an intersection with I-10 at Las Cruces, New Mexico (approximately 25 miles north of El Paso, Texas), to I-90 in Buffalo, Wyoming (approximately 60 miles south of the Wyoming-Montana border). Except for the major cities listed above, it runs through mainly rural areas.
I-25 in New Mexico
I-25 begins at Exit 144 of I-10 in Las Cruces, which is just south of the New Mexico State University campus. Throughout its 462.12-mile length in New Mexico, I-25 runs concurrently with U.S. Route 85 (US 85). From Las Cruces to Santa Fe, I-25 follows the route of El Camino Real de Tierra Adentro (the Royal Road of the Interior Land). When I-25 reaches the town of Truth or Consequences, it parallels Elephant Butte Lake State Park.
As I-25 nears Albuquerque, it runs concurrently with US 60. Further north, State Road 6 (the former Route 66), intersects I-25 in Los Lunas. As I-25 runs through Albuquerque it is named the Pan American Freeway. There is a major interchange of I-25 and I-40 in Albuquerque; it is named “the Big I.”
The Big I is northeast of downtown Albuquerque. The original exchange between the two interstate highways was known as “The Crossroads of the Southwest.” When it was opened to traffic in 1966 the directional interchange with left-side ramps was built to move military personnel and other long-distance traffic through Albuquerque. The original interchange was built to handle about 40,000 vehicles during a normal daily commute. By 2000, traffic had increased to 300,000 vehicles per day.
When the Big I was rebuilt a five-level systems interchange was constructed to connect I-25 and I-40. The three-phase project rebuilt sections of I-25 and I-40 within 1.5 miles of the interchange. Among the changes were a project to straighten an S-curve along I-25. In addition, both highways were widened by one lane in each direction and high-speed flyovers replaced the left-side ramps. The frontage road system adjacent to the highways was completed and expanded to improve traffic flow. At a cost of just under $300 million, the work began on June 30, 2000 and was completed less than two years later (May 25, 2002).
I-25 continues northward after leaving Albuquerque; the highway curves to the northeast approaching Santa Fe. While I-25 continues mainly northbound after leaving Santa Fe, the highway heads southeast for approximately 45 miles. It runs through Santa Fe National Forest and also crosses Glorieta Pass, which has an elevation of 7,452 feet. At Blanchard (population about 13,000), I-25 turns north toward Las Vegas. The interstate maintains a north/northeast orientation leaving New Mexico. The highway traverses Raton Pass (at an elevation of 7,798 feet) and enters Colorado.
I-25 in Colorado
As I-25 runs from Santa Fe to Trinidad, Colorado, the highway follows the route of the Santa Fe Trail. In Colorado, I-25 runs for just under 300 miles. Along that length, I-25 and US 85 are concurrent. For its entire length in Colorado, the Rocky Mountains are clearly visible.
I-25 serves all the major cities in Colorado that are east of the Rocky Mountains, including Denver, Colorado Springs, Pueblo, Fort Collins and Greeley. There have been large-scale renovations to the highway in Colorado (the Transportation Expansion Project in Denver and the Colorado Springs Metropolitan Interstate Expansion).
The projects, as well as similar ones in New Mexico, were necessary because these sections of I-25 were inadequately designed and constructed (among other issues the pavement was rapidly deteriorating). Another reason for the renovations was that the population in the urban areas along I-25 (such as Albuquerque, Colorado Springs and Denver) tripled or even quadrupled much earlier than had been anticipated back in the 1950s and 1960s. The highway as originally constructed was inadequate for the major increase in traffic that occurred over the decades.
The largest multi-modal transportation project in Colorado history occurred in Denver, beginning in September 2001. Nicknamed “T-REX,” the project’s purpose was to relieve the congestion on I-25 and I-225 (which runs between I-25 and I-70 in Denver).
I-25’s predecessor was the Platte Valley Drive Road, which was 11.2 miles long. Planning for it began in 1944 and construction began in November 1948. The road became known as the Valley Highway and it opened in November 1958. The Valley Highway parallels the South Platte River through Denver’s downtown area and it was built below ground level in some areas. By 1998, both the section of I-25 known as Valley Highway and I-225 were well over capacity on a daily basis.
The traffic jams on the two highways led to a partnership between the Colorado Department of Transportation (CDOT) and the Regional Transportation District (RTD), which is responsible for the Denver light rail system.
In 1997 the Denver Regional Council of Governments adopted recommendations that included 19.7 miles of new double-track light rail, 13 new light-rail stations, expansion of travel lanes to coincide with interchange improvements and bridge replacement projects, and HOV lanes.
I-25 has other names as it passes through the state’s other population centers. It is the Ronald Reagan Highway in El Paso County; between the northern border of Pueblo County and the New Mexico state line the highway was named the John F. Kennedy Memorial Highway in honor of President Kennedy’s support of water resources development in the Arkansas River Valley.
There are a number of key military and air bases and institutions along or near I-25 in Colorado, including Buckley Space Force Base, the Cheyenne Mountain Complex headquarters of NORAD, Fort Carson, Peterson Air Force Base and the United States Air Force Academy.
The highway crosses the Palmer Divide between Denver and Colorado Springs. While some of the highway’s most scenic views of the Rocky Mountains and its foothills are in this area, blizzards and high winds (particularly over Monument Hill) can cause traffic problems during the winter.
I-25 leaves Colorado in the north about eight miles south of Cheyenne, Wyoming.
I-25 in Wyoming
I-25 is slightly longer in Wyoming than it is in Colorado (301 miles compared to just under 300 miles). After I-25 runs through Cheyenne the highway continues north to Douglas (population 6,400), passing many plateaus as well as numerous railroad tracks. Very long trains are often seen moving parallel to the highway. Around Douglas, I-25 curves westward toward Casper (population around 60,000). After leaving Casper, I-25 runs due north to Buffalo (population under 5,000). I-25 ends at an interchange with I-90.
In summary, I-25 is the major north-south corridor for the three states. Like other interstate highways, the increases in population and traffic have meant that I-25 has had to be rebuilt and widened in the urban areas it passes through.