The new US 36 Bike Path from Westminster to Boulder was completed last spring.
I was impressed when just a couple months later on a whim I tried using Google Maps to plot a bicycle route and it already knew about it!
This initially looks like it is taking the highway, but zoom in and you will see it is really taking the bike path which parallels the highway:

https://www.google.com/maps/dir/39.9...a=!4m2!4m1!3e1