Interstate business routes are roads connecting a central or commercial district of a city or town with an Interstate bypass. These roads typically follow along local streets often along a former US or state highway that had been replaced by an Interstate. Interstate business route reassurance markers are signed as either loops or spurs using a green shield shaped sign and numbered like the shield of the parent Interstate Highway.

Interstate 25 (I-25), also known as the Pan-American Freeway, is a major Interstate Highway in the western United States. It is primarily a north–south highway, serving as the main route through New Mexico, Colorado, and Wyoming. I-25 stretches from I-10 at Las Cruces, New Mexico to I-90 in Buffalo, Wyoming. It passes through or near Albuquerque, New Mexico; Pueblo, Colorado; Colorado Springs, Colorado; Denver, Colorado; Fort Collins, Colorado; and Cheyenne, Wyoming. The I-25 corridor is mainly rural, especially in Wyoming, excluding the Albuquerque metropolitan area and the Front Range urban corridor from Pueblo to Cheyenne.