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Chapter 4
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Design Criteria
4.11 Sidewalks

SDOT’s goal is to provide an interconnected network of sidewalks and walkways that allow pedestrians to safely access their destinations including transit stops, places of employment, recreation facilities, schools and residences.

SDOT recognizes and supports the range of benefits a well-designed streetscape provides for all pedestrians, including people with disabilities. For this reason, SDOT reviews streetscape design elements very carefully to ensure that the materials, dimensions and design elements meet safety and accessibility requirements. In addition to the aesthetic and practical benefits of a well-designed streetscape, SDOT must meet state and national safety and access standards for streetscape design.

The streetscape is broken into three parts, the Frontage Zone, Pedestrian Zone and Landscape/Furniture Zone plus Curb. The locations of these zones are defined as follows:

The Landscape/Furniture Zone (including the curb) is defined as the area between the roadway curb face and the front edge of the walkway. The minimum width of this zone is 5½ ft feet except in locations adjacent to high and intermediate capacity transit stations. Objects in the landscape/furniture zone must be setback a minimum of 3’ from the face of the street curb. This zone buffers pedestrians from the adjacent roadway and is the appropriate location for street furniture, art and landscaping. It is also the preferred location for street trees, and other elements such as pedestrian lighting, hydrants and below grade utility hatch covers. Transit Zones are also located in the landscape/furniture zone and are designated for transit customer waiting, loading and alighting and may include transit signage, shelters, benches, litter receptacles, and pedestrian scaled lighting. Any landscaping or other objects proposed for this zone must comply with City of Seattle permitting requirements and design criteria.

The Pedestrian Zone is the area of the sidewalk corridor that is specifically reserved for pedestrian travel. The minimum width of this zone is 6 feet, except in locations adjacent to high and intermediate capacity transit stations. Street furniture, plantings, and other fixed items should not protrude into travel routes.

The Frontage Zone is defined as the area between the property line and walkway. Where sufficient right-of-way exists, a frontage zone should be provided that is a minimum of 2 feet wide, except in locations adjacent to high and intermediate capacity transit stations. Frontage zones can accommodate sidewalk cafes, store entrances, retail display or landscaping. A frontage zone is not needed if the sidewalk corridor is adjacent to a landscaped space.

Streetscape Zones

Streetscape Zones

4.11.1 Links to Standard Plans and Specifications

Standard Plan 420: Concrete Sidewalk Details
Standard Plan 421: Sidewalk with a Monolithic Curb
Standard Plan 422: Curb Ramp Details
Standard Plan 430: Type 430 Driveway
Standard Plan 431: Concrete Driveway Placed with Sidewalk Construction

4.11.2 Design Criteria

Standard construction of sidewalks: A standard sidewalk is constructed of Portland cement concrete and is located at least 5½ feet from the face of the curb and 2 feet from the property line. The sidewalk may be located closer to the property line when necessary to attain the minimum 5 foot planting strip width and 6 foot sidewalk.

Construction of new sidewalks: On streets where the existing sidewalks are greater than 6 feet in width, the new sidewalk shall match the existing sidewalk width. In residential zones, when more than half the block on the project side of the street already has a sidewalk and planting strip, new sidewalks and planting strips may conform to the existing location, unless otherwise direct by SDOT.  On streets in non-residential zones where the existing sidewalk is not in the standard location, SDOT shall determine the location of any new sidewalk or sidewalk replacement, based on the need for street trees and the desire to retain existing neighborhood character. New concrete sidewalks may not be installed without a curb.   If a concrete sidewalk is required and there is no curb, a concrete curb shall be installed in the permanent location. In many cases, this will necessitate the installation of additional roadway pavement and drainage facilities.

Sidewalk width: Sidewalks shall be a minimum of 6 feet of unobstructed, linear sidewalk space that is free of street furniture, street trees, planters, and other vertical elements such as poles, fire hydrants and street furniture. Point obstructions such as poles and fire hydrants may encroach into the sidewalk area, but the sidewalk must have 5 feet clear width remaining. 

Wider sidewalks are required in some cases consistent with the Land Use Code or when the sidewalk must be placed adjacent to the curb because of topography or right of way limitations.  Sidewalks may be located adjacent to the curb when there is inadequate right of way or in steep topography areas where grading to a full street width would cause too great of an impact.  Steep topography areas are defined by an 8-foot or more elevation difference between the existing grade and the established street grade at the right of way line.  Sidewalks adjacent to the curb on non-arterial streets shall be a minimum of 8 feet wide.  Sidewalks adjacent to the curb on arterial streets outside of downtown shall be a minimum of 10.5 feet wide.

Sidewalk path of travel: Sidewalks should keep as much as possible to the natural path of travel parallel to the improved roadway. Ideally, they will align with the crosswalk. While sidewalks do not need to be perfectly straight, curves that direct the pedestrian away from the natural path should not be introduced solely for aesthetic reasons.

Setback: A three foot distance between vertical objects on the sidewalk and travel lanes in the roadway is required to minimize conflicts with vehicle activity. Relocation of existing utilities may be required to meet clearance requirements.

Clearance from obstructions: The sidewalk shall be clear of all vertical obstructions, such as poles, fire hydrants, street furniture, and other elements for a width of at least 5 feet. These obstructions should be placed in the landscape / furniture zone or behind the sidewalk.  Relocation of existing utilities may be required to meet clearance requirements.

Utility access points: Where practical, handholes, vaults, and other utility access points shall be located out of the sidewalk area and in the landscape/furniture zone. Where this is not practical, these access points must match the level of the sidewalk and be coated with a non-slip surface.

Slope: Sidewalk cross slope must be a minimum of 0.5% but may not exceed 2%.

Sidewalk Finish:  Sidewalks shall be constructed and finished per the Standard Plans and Specifications.  Any other treatments (non-standard scoring patterns, coloring, texturing) must be approved by SDOT and either the design review board or the design commission. 

Visibility: No obstructions to pedestrian visibility should be present within 30 feet of an intersection. These include parked cars, street trees, signal control boxes, sandwich boards, utility poles and landscaping mounds.

Variations from standard sidewalk construction: In general, variations from standard sidewalk construction are required to meet ADA requirements. Additionally, on residential streets where natural drainage is being installed, variations will be considered based on planning and design principles defined in Chapter 6.4 Green Stormwater Infrastructure.

Asphalt pedestrian walkways: There may be locations where asphalt walkways are appropriate on non-arterial streets such as industrial zones as specified by the Land Use Code. Please refer to the figure for more detailed information.
Figure 4-15: Asphalt Pedestrian Walkway - for use in industrial zones only, as allowed by the Land Use Code
Figure 4-16: Asphalt Pedestrian Walkway 10 Feet or More From Existing Roadway - for use in industrial zones only, as allowed by the Land Use Code

Maintenance responsibility: The area between the curb and property line, including sidewalks, is the maintenance responsibility of the abutting property owner. When the existing sidewalk adjacent to a project is in disrepair or is damaged during construction, it shall be repaired or replaced by the property owner.

Accessibility:  Pedestrian facilities shall be designed to allow all users to logically connect to other pedestrian facilities (e.g. – length of sidewalk transitions and placement of objects near walkways).  They shall be in compliance with current ADA requirements in all cases.  Sidewalks and walkways should be constructed with accompanying curb ramps, including companion ramps, as required by current ADA standards.

Sidewalks in the vicinity of transit stations: Applicants proposing new development in the block adjacent to a high or intermediate capacity transit station must accommodate high volumes of pedestrians in the vicinity as follows.
In the block adjacent to the transit station, the sidewalk shall be 18-25 feet as follows:

  • Frontage zone: (3 feet) If the project has a plaza or other space accessible to pedestrians and free of obstructions adjacent to the property line, the frontage zone requirement may be waived.
  • Pedestrian zone: (10-12 feet) The pedestrian zone shall consist of a paved linear walkway that is free from obstructions. The following shall be considered when establishing the dimension of the Pedestrian Zone:
    • Ridership projections for the station;
    • Anticipated pedestrian volumes from adjacent land uses;
    • Right-of-way dimensions;
    • Block length; and
    • Location of bus transfer zones.

SDOT staff will work with the applicant to make the final determination of required sidewalk width.

  • Landscape/Furniture zone plus curb: (5-10 feet) Landscape requirements for the project defined in the Land Use Code (SMC Title 23) can be met within the Landscape/Furniture Zone (they are not additive). The following shall be considered when establishing the dimension of the Landscape/Furniture Zone:
    • Available right-of-way dimensions;
    • Urban design priorities established by the City or Transit Agency; and,
    • Direction of adopted Street Design Concept Plan or other adopted plans.
    • Improvements in these zones shall meet or exceed the accessibility requirements defined by ADA as well as applicable local and state standards.
Additional improvements within 1/4 mile of station entrance: SDOT also requires curb ramps with tactile warning strips at legal crosswalks (refer to Chapter 4.8.2 Intersection Design Criteria) and smooth accessible sidewalks within a quarter mile of the station entrances. SDOT will require the transit agency to assess the conditions within the quarter mile of the station entrance, and add or repair existing sidewalks and curb ramps to provide access to the stations consistent with ADA guidelines. In some cases, consistent with City policy in support of transit oriented development, a project may be allowed to meet the total required sidewalk width and include building columns in between the Pedestrian and Landscape/Furniture Zones.  In this scenario, the minimum dimension of clear, unobstructed sidewalk width shall be retained within the Pedestrian Zone.
4.11.3: Design Considerations

Width: Provide adequate sidewalk width, especially at locations such as transit stops where pedestrians can be expected to congregate.

Buffers: Sidewalks and walkways should be buffered from the motor vehicle lane by a planting strip, street furniture, parked cars or a bike lane.

Sidewalks in the vicinity of high and intermediate capacity transit stations: Consistent with the City of Seattle Comprehensive Plan policies that encourage pedestrian access to and from public transit facilities, especially in Urban Centers and Villages, the following shall be considered:

  • High and intermediate capacity transit stations have unique needs for pedestrians due to the high volumes of pedestrians exiting stations and onto the adjacent streets. Transit agencies are typically required to size station plazas and waiting areas according to anticipated queuing and exiting volumes. However, the requirements do not typically extend outside the boundaries of the station site.
  • The sidewalk on the street fronting the station is the primary location for high volumes of pedestrians congregating, making transfers to other modes or walking to a destination. This first block is where the need for wide sidewalks that are well-buffered from moving traffic is greatest. In some cases, anticipated pedestrian volumes, major pedestrian generators or other special conditions may require the improvements to exceed one block in length (e.g. hospitals, schools, community centers, libraries and parks).
  • Additional improvements to pedestrian facilities are needed within a 1/4 mile of the station site to support and encourage safe pedestrian access (e.g. wide sidewalks, buffers, curb ramps).
continue to section 4.12 »   
Latest Online Manual
Detailed Table of Contents
Chapter 4
Design Criteria
4.1 Introduction
4.2 Street Classifications and Street Types
4.3 Design Criteria General Notes
4.4 Grading
4.5 Design Cross Section
4.6 Roadway Width
4.7

Roadway Pavement

4.8 Intersections
4.9 Driveways
4.10 Curbs
4.11 Sidewalks
4.12 Crosswalks
4.13 Bicycle Facilities
4.14 Street Trees and Landscape Architectural Standards
4.15 Introduction to Utilities Design Criteria
4.16 Street Lighting
4.17 Street Drainage, Storm Drains and Sewers
4.18 Water Mains
4.19 Fire Protection
4.20 Seattle City Light
4.21 Clearances
4.22 Structures in the Right-of-Way
4.23 Cul–de–sacs and Turnarounds
4.24 Traffic Operations
4.25 Transit Zones
4.26 Street Furniture, Public Art and Unique Objects in the Public Right-of-Way
4.27 Access Easements
4.28 Contact Information
   
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