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What Are Detectable Warning Surfaces?

While walking down most city and residential sidewalks, it is hard to miss the thick, plastic like bumpy surfaces that cap each sidewalk end. The brightly colored, rigid surfaces are not there for decor purposes or even for better grip during rainy or otherwise wet days. These surfaces serve a greater purpose. For people with a sight impairment, these detectable warning surface help them navigate on their own while outdoors safely. The texture alerts people that use walking sticks or sight assistant canes that the sidewalk is beginning or ending when they are moving between streets. Without the textured surface, walking through public streets can be dangerous and difficult for sight impaired people.

But, what are these detectable warning surfaces made of and how are they created to ensure that they are consistently effective for those that need them most?


This type of warning surface is placed in fresh cement likely just poured to create a new sidewalk or construction site. Once the pavement has dried and become firm, the warning surface is set in place. This is essential as it ensures that the textured surface will not move or shift with weather changes or environmental changes. This makes sure that they are effective.

Surface Applied

The surface applied type of detectable warning surface is very similar to the cast-in-place option. The main difference is that the cast-in-place option can be a bit more time consuming as it requires the concrete to be fresh and wet in order for it to dry in place. The surface applied version is a quicker option that can be completed in minutes. It is placed on top of the concrete and fitted permanently on top of it to ensure that it stays in place to be effective through weather changes and use over time.

Cast-in-place Replaceable

For some locations that are more high traffic, like a full city as opposed to a small residential area, detectable warning surface can endure more wear and tear and will need to be replaced. The cast-in-place replaceable option is similar to the original cast-in-place option but, there is a major difference. They are fitted the same, in wet concrete in order to dry as a part of the sidewalk. However, these warning surfaces have two layers. This allows the city or town to remove the top layer once it has become warn and damaged with a fresh new surface underneath. This saves the city from having to remove the damaged pad from the concrete completely in order to remove the damaged surface.