Protected bike lanes have some sort of physical, stationary, vertical separation between moving motor vehicle traffic and the bike lane. Examples of vertical separation include plastic posts, bollards, curbs, planters, raised bumps or parked cars. Protected bike lanes can be at street level or raised, either to sidewalk level or a level in between street and sidewalk level. Paint alone does not create a protected bike lane.

Protected bike lanes are part of the street grid. In some instances, a protected lane may be separated from the road by landscaping or other features, but it runs parallel and proximate to the roadway. This distinguishes protected bike lanes from off-street pathways that follow waterways or rail corridors.

Protected bike lanes must define and allocate space exclusively for people on bikes, not shared with pedestrians or motorized traffic except for brief mixing zones where necessary and at intersections. If the designs are sidewalk level, there must be separate, identified space for people on bikes and people on foot in order for the facility to be considered a protected bike lane.