You may have seen or heard about the yellow detectable warning strips that SDOT installs at the bottom of curb ramps and at transit platforms. The “yellow bumps” (truncated domes) on the detectable warning surface help provide important tactile information to people that have limited or no vision.
Truncated Domes at transit platform in South Lake Union
Did you know that SDOT is also working to provide additional tactile features that help people get where they need to be? Sometimes we have bicycle facilities next to walkways and it is helpful to let people with limited or no vision know where one starts and the other ends. A raised edge or strip, also known as a directional tactile feature, can help someone detect the edge of the walkway with their white cane. As a person sweeps their cane from side to side, they can detect the raised surface and remain on the intended path.
Raised edge defines separation between bicycle track and walkway
SDOT is also beginning to place these raised tactile surfaces at transit islands and platforms. In some cases, transit platforms and sidewalks are separated by dedicated bike lanes. A raised surface can help delineate the sidewalk from the bike lane, and truncated domes can indicate the intended crossing to access the transit island.
Raised edge defines separation between bicycle lane and walkway at transit island
The use of these raised tactile surfaces is somewhat of a new development. SDOT is currently working with local and regional agencies that support the blind for feedback on these features, and we also participate in trainings and nationwide workshops to better understand how to provide good information for those that have limited or no vision.
If you have any questions about accessibility within the Seattle public right-of-way, we encourage you contact SDOT’s ADA Coordinator, Michael Shaw. He can be reached at (206) 615-1974 or by email at Michael.Shaw@seattle.gov.