I’m one of those people that likes to classify things. Is taxonomist the right description? Anyway, for me, it’s important to be buzz-word compliant but with a purpose: Once I have the list in my head, I can hang the details off each peg. So it appears that bicycle infrastructure is classified something like this:
Separate Facility (a.k.a. Class I) – A non-motorized facility, paved or unpaved, physically separated from motorized vehicular traffic by an open space or barrier. Also called Bicycle Path, Bike Trail, Non-motorized Trail, Multi-purpose Trail or some combination thereof.
Bike Lane (a.k.a. Class II) – A portion of a roadway that is designated by striping, signing and pavement markings for the preferential or exclusive use of bicyclists. Most often these are done in couplets, each one being one way and adjacent to the outside through travel lane. Also called Bicycle Lanes.
Bike Route (a.k.a. Class III) – A segment of road designated by the jurisdiction having authority, with appropriate directional and informational markers, but without striping, signing and pavement markings for the preferential or exclusive use of bicyclists. Also called Bicycle Route.
Bike Friendly (a.k.a. Class IV) – A roadway not designated by directional and informational markers, striping, signing nor pavement markings for the preferential or exclusive use of bicyclists, but containing appropriate bicycle-friendly design standards such as wide-curb lanes and bicycle safe drain grates.
This is all stolen from this site, which in turn seems to have stolen it from AASHTO.
I have simplified this further:
I don’t know if those classes are AASHTO or not. MOAR RESEARCH!
Updated to add a few links to similar resources: