Interstate 80 (East-West)and Interstate 25 (North-South)

Interstate 80 and Interstate 25 are the only two roads in the entire state that have more than one lane traveling in each direction.

Interstate 80 (Even numbers run east to west)
Interstate 80 (I-80) is the second-longest Interstate Highway in the United States, following Interstate 90. It runs from west to east.

It is a transcontinental artery running from downtown San Francisco, California to Teaneck, New Jersey in the New York City Metropolitan Area.

I-80 is the Interstate Highway that most closely approximates the route of the historic Lincoln Highway, the first road across America. The highway roughly traces other historically significant travel routes in the Western United States: the Oregon Trail across Wyoming and Nebraska, the California Trail across most of Nevada and California, and except in the Great Salt Lake area, the entire route of the First Transcontinental Railroad.

From near Chicago, Illinois, east to near Youngstown, Ohio, Interstate 80 is a toll road, containing the majority of both the Indiana Toll Road and the Ohio Turnpike. I-80 runs concurrent with Interstate 90 from near Portage, Indiana to Elyria, Ohio. I-80 becomes the Keystone Shortway, a freeway built across rural northern Pennsylvania expressly for I-80, with its eastern origin at its junction with the New Jersey Turnpike and Interstate 95 just west of the George Washington Bridge entering New York City.

Interstate 25(Odd numbers run north and south).
Interstate 25 (I-25) is an Interstate Highway in the western United States. It is primarily a north–south highway. I-25 stretches from Interstate 10 at Las Cruces, New Mexico, (approximately 25 miles (40 km) north of El Paso, Texas), to Interstate 90 in Buffalo, Wyoming, (approximately 60 miles (97 km) south of the Montana/Wyoming border).

Interstate 25 is the main north–south expressway through Wyoming, Colorado, and New Mexico. From north to south, it passes through or near Casper, Wyoming; Cheyenne, Wyoming; Fort Collins, Colorado; Denver, Colorado; Colorado Springs, Colorado; Pueblo, Colorado; Raton, New Mexico; Las Vegas, New Mexico; Santa Fe, New Mexico; Albuquerque, New Mexico; Socorro, New Mexico; Truth or Consequences, New Mexico and Las Cruces, New Mexico. The I-25 corridor in Colorado and New Mexico is urbanized, like the long heavily-urbanized stretches of Interstate 5, Interstate 75, and Interstate 95 especially through the Denver metropolitan area.

The part of I-25 in Colorado passes just east of the Front Range of the Rocky Mountains. That stretch was recently involved in a large-scale renovation named the T-REX (TRansportation EXpansion) in Denver, and the COSMIX (Colorado Springs Metropolitan Interstate Expansion). These projects and others in New Mexico were necessitated because these stretches of I-25 were inadequately designed and constructed originally (the pavement was deteriorating rapidly), and also because urban areas like Denver, Colorado Springs, and Albuquerque had tripled and quadrupled in population much earlier than anyone had anticipated back in the 1950s and 1960s. Major highway work for the T-REX project ended on August 22, 2006. The COSMIX project was completed in December 2007. Several other smaller improvement projects for I-25 are still ongoing within Colorado and New Mexico.