Detectable Warning Surface

Usage: Standard

A detectable warning surface (DWS) provides a continuous detectable edge between the pedestrian circulation path and the roadway at a flush curb. The surface, in a color that contrasts with its surroundings, helps to guide persons who are blind or have low vision DWS may also be referred to as tactile domes or raised domes.

Bay Ridge Avenue, Brooklyn
Red DWS

Benefits

  • Provides a cane-detectable warning wherever raised curbs are not present between pedestrian access routes and vehicular areas, transit platforms, or other potential hazards where a pedestrian has encountered a potential hazard and should stop, or that they have reached a safe area

Considerations

  • Follow all final rules promulgated by the United States Department of Justice and the United States Department of Transportation under Title II of the Americans with Disabilities Act (ADA)
  • Carefully consider the materials surrounding the DWS as well as proposed installation methods given the underlying material
  • Slope and context needs to be considered where the installation is occurring to ensure adequate coverage of DWS
  • NYC DOT generally employs plastic DWS mats embedded in concrete. However, other materials are permitted (e.g. stone, cast iron, etc.). Consider material durability and maintenance when selecting and installing DWS
  • Stone DWS can be prone to cracking and difficult to replace if installed improperly
  • LPC review is required when installing DWS on historic materials

Application

  • DWS should be employed where pedestrians are being directed to cross a travel lane
  • DWS is required at all Pedestrian Ramps
  • DWS must be incorporated into Raised Intersections, Raised Crosswalks, and Shared Streets
  • Consider using DWS in conjunction with other approved tactile warning surfaces to define Grade Separated Bike Lanes
  • NYC DOT also utilizes DWS at certain Bus Bulbs consistent with the SBS Design Guidelines

Design

Specification source: DOT Standard Specifications Section 4.13 DWS

Details source: DOT Standard Details of Construction H-1011-9

  • The design and construction of DWS must comply with all final rules promulgated by the United States Department of Justice and the United States Department of Transportation under Title II of the Americans with Disabilities Act (ADA) and NYC DOT Standard Details of Construction Drawing #H-1011 (DWG #H-1011), and local rules, specifications, and bulletins
  • DWS must provide color contrast with the adjoining sidewalk
  • The following sidewalk materials, or those that are visually approximate, must utilize detectable warning surfaces that are an approximate visual match to the Red color of SAE Standard AMS-STD-595 #31350:
    • Unpigmented concrete
    • Unpigmented concrete with silicon carbide surface treatment
  • The following sidewalk materials, or those that are visually approximate, must utilize detectable warning surfaces that are an approximate visual match to the Bright White of SAE Standard AMS-STD-595 #27925:
    • Pigmented Concrete: Dark (i.e. "Commercial Grey" pigmented concrete per Section 4.13)
    • Pigmented Concrete: Dark with silicon carbide (i.e. “Commercial Grey” pigmented concrete with silicon carbide surface treatment per Section 4.13)
    • Pigmented Concrete (Historic Materials) (i.e. “Granite” pigmented concrete per Section 4.13)
    • Stony Creek pink granite
    • Virginia Mist granite, including the Waterstorm, Thermal, and Split finishes
    • Red brick pavers
    • Black asphalt
  • DWS is required for shared Pedestrian and Bike ramps. Shared use ramps for pedestrians and bicycles must extend the full width of the shared use path
  • DWS must be installed at all flush curb locations where the pedestrian access route crosses a vehicular travel lane
  • DWS must be installed across the full width of flush curb, including full ramp width, full bottom landing width, full blended transition width, and full cut-through width (where applicable)
  • DWS must be installed for a minimum length of 24 inches in the direction of pedestrian travel
  • Embedded DWS as well as most pre-cast or surface-applied DWS must be installed on a planar surface to prevent warping
  • Size and space of truncated domes must comply with DOT and ADA Standards
  • Pre-formed radial DWS is permitted
  • DWS must be installed per the manufacturer’s recommendations

Maintenance

  • Adjacent property owners are generally responsible for maintaining this material
  • To ensure a good appearance of color and texture, surfaces should be cleaned using mechanical sweepers, power brooming, or hand brooming
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