Design Criteria

The following design principles apply to both Green Streets and Neighborhood Green Streets:

• Emphasize pedestrians and open space over other street functions. Green Streets serve both as pedestrian gathering places, and as pedestrian corridors connecting activity areas. They are designed to provide an inviting, attractive, and safer streetscape for pedestrians, bicyclists, and transit patrons. In certain cases, Green Streets may be designed to reduce vehicular travel speeds to the point where it becomes reasonable for pedestrians and vehicles to “share” space in the street right-of-way. In Seattle, a well-known example of this type of “shared street” is Pike Place.
• Design should complement and enhance adjacent land uses. Buildings in much of Downtown Seattle are required to have pedestrian friendly features at the ground floor (e.g., transparency, weather protection, prominent entrances). Green Street design should complement these features with improvements in the street right-of-way that encourage pedestrian activity.
• Keep traffic speeds and volumes low. Green Streets are typically designated on non-arterial streets and are expected to have lower traffic volumes and speeds than other streets in the City. One of the key factors to making a street safer and inviting for pedestrian is maintaining slow vehicle speeds and relatively low vehicle volumes. This is why Green Streets are designated on streets that do not, or are not anticipated to, contribute significantly to vehicle capacity in the area. Often, Green Streets are designated on non-through streets or streets that are not a key part of the street grid (e.g., dead ends and short segments of street created by the collision of street grids) Design features that tend to reduce vehicular travel speeds are good choices for Green Street designs (Street Types). A Green Street or Neighborhood Green Street designated on an arterial street must provide for traffic speeds and volumes that can support appropriate arterial operations and the mobility needs of all people.
• Respond to site specific conditions. Generally, Green Streets are conceived around a unified design concept–one that reflects or embellishes the unique character of the site. Ideally, such a design concept would be applied to every block of the Green Street. Green streets offer the opportunity to reinforce unique conditions or respond to site specific opportunities (e.g., solar access, historic buildings or street features, topography, stormwater mitigation, views).