California Code, Streets and Highways Code - SHC § 890.4

(a) Bike paths or shared use paths, also referred to as “Class I bikeways,” which provide a completely separated right-of-way designated for the exclusive use of bicycles and pedestrians with crossflows by motorists minimized.

(b) Bike lanes, also referred to as “Class II bikeways,” which provide a restricted right-of-way designated for the exclusive or semiexclusive use of bicycles with through travel by motor vehicles or pedestrians prohibited, but with vehicle parking and crossflows by pedestrians and motorists permitted.

(c) Bike routes, also referred to as “Class III bikeways,” which provide a right-of-way on-street or off-street, designated by signs or permanent markings and shared with pedestrians and motorists.

(d) Cycle tracks or separated bikeways, also referred to as “Class IV bikeways,” which promote active transportation and provide a right-of-way designated exclusively for bicycle travel adjacent to a roadway and which are separated from vehicular traffic. Types of separation include, but are not limited to, grade separation, flexible posts, inflexible physical barriers, or on-street parking.