Truncated Domes

Neil Lau from Visul Corporation installs their truncated dome product at the corner of Main and South streets near the post office. The purpose of the truncated domes is to provide a tactile surface warning of the location of the street for persons with visual disabilities. Detectable warnings were originally required in 1991, but the installation of detectable warnings was suspended to allow for research on the best type of detectable warning. In 2001, the truncated dome surface was chosen as the best type of detectable warning. Since that time, all new curb ramps must have truncated domes.

Unfortunately, the technology for truncated dome surfaces has not been perfected. The cheapest method is to stamp the surface into newly-poured concrete. However, as seen above, this method doesn't hold up well to snow shovels/plows and different weather conditions.

You can see other truncated dome products at the Washington Street Education Center and near the McKune Memorial Library. The tiles for the truncated domes near the Post Office are made from a combination of polyurathane and limestone dust. The tiles are glued to the surface with an adhesive. The company has had good success with the durability of the tiles to winter weather, snow plows, rain, etc.

The installation near the Post Office is a demonstration to determine how well it holds up through the winter and how well it adheres to the brick paver surface. The cost of the tiles and adhesive is $128, excluding any labor and equipment costs for installation. Eight of these surfaces are required at each four-way intersection. Multiply $1,024 by each four-way intersection in the City, then you will have some idea of the cost to retrofit every sidewalk in the City.