"Right now, Seattle's various facility types are essentially just colloquialisms," said Seattle Bicycle Advisory Board Chair Blake Trask. "In order to make facilities more transferable and usable across the city, some sort of standardization is necessary, particularly as Seattle begins its five-year Bicycle Master Plan Update."
SDOT does not, in fact, have official definitions for much of the new infrastructure they're installing. According to SDOT Bike Program manager Sam Woods, the official definitions for new facility types will be included in next year's five-year BMP update. For now, Woods says, the agency uses the generic term "buffered bike lane" to refer to bike lanes with a painted buffer (like the ones on 7th Ave and N 130th St). SDOT refers to a bike lane completely protected by parked cars as a "parking separated bike lane" (none of these exist yet in Seattle). Linden Ave. will be a hybrid between the two types because it includes sections that lack a parking lane barrier.
One of the root causes of all the confusion and inconsistency is the outdated American Association of State Highway Transportation Officials (AASHTO) manual. This "engineer's greenbook" is the go-to standard for facility design, but, as Cascade Bicycle Club Advocacy Director David Hiller points out, the organization's "last version of the bike/ped design is now ancient." The latest version was written in 1999 (with a 2004 update), before most of America's new protected on-road facilities even existed.
Because AASHTO is lagging, another group, the National Association of City Transportation Officials (NACTO), has taken it upon themselves, with their Cities for Cycling project, to "catalog, promote and implement the world’s best bicycle transportation practices in American municipalities" by drafting a comprehensive Urban Bikeway Design Guide.
Cities for Cycling's online catalog explains design features, advantages, disadvantages, and design considerations for modern, semi-experimental facilities such as bike boxes, boulevards, bike signals, buffered bike lanes, cycle tracks, colorized pavement, and others. By NACTO's definition, the proposed Linden Ave "parking separated bike lanes" could be considered cycle tracks.
It is widely (though, of course, not universally) accepted in the bicycle planning world that separated facilities are key to significantly increasing the number of bicyclists. "These kinds of facilities are going to be critical in helping us [achieve] our goal of tripling the number of riders in Seattle over 10 years," Hiller says. Having standard definitions and standard facilities designs will improve SDOT's tool box and help the agency implement the best facilities they can to increase bicycling in Seattle.