In my experience in Colorado, the right lane is usually empty and it's often easier to go faster than traffic in the right lane (at least on sections of freeway

In my experience in Colorado, the right lane is usually empty and it's often easier to go faster than traffic in the right lane (at least on sections of freeway without exits close together). The left lane is usually traveling at least 20mph faster than the limit (on I-25 anyway). 85mph in a 65mph zone is the norm.