Prior to I-25, there was a different main highway that connected Denver to several of the Northern Front Range cities in Colorado. The number of this highway has changed a few times during the past century, but its general corridor has remained the same: it still runs through Ft. Collins, Loveland, Berthoud, Longmont, Lafayette, Broomfield, Westminster, and Denver. Not all of those cities had even been established at the time of the 1916 map shown below, but the highway corridor running along the Northern Front Range is readily apparent (going forward I will refer to this road as the NFRH, for "North Front Range Highway"):
Our planet is spheroidal in shape, which means its surface is curved. So making a map of the Earth's surface involves taking something that is curved and projecting it onto something flat (such as a piece of paper or a computer screen). But this flattening inherently causes some distortion from reality. It is not possible for any one map projection to preserve all of the following: 1.) direction, 2.) shape, 3.) area, and 4.) distance. So when a cartographer chooses a particular map projection, they are choosing to preserve one or more of those traits at the expense of others.