Durability of truncated dome warnings on existing curb ramps.

PDFTech ReportFHWA-OR-RD-05-06SPR 304-241RampsDurabilityWarning signsDetectable warning surfacesRetrofittingAdhesionConcreteColorOregonOregon. Dept. of Transportation. Research UnitKirk, Alan R.Oregon. Dept. of Transportation. Research UnitUnited States. Federal Highway AdministrationUS Transportation CollectionIn 2002 the Federal Highway Administration (FHWA) notified the Oregon Department of Transportation (ODOT) that that the state was required to use truncated dome detectable warnings on curb ramps. Products appropriate for use on cured concrete surfaces were of particular interest to ODOT. A research project was undertaken to monitor four products that appeared to be best suited for retrofitting existing curb ramps. Over a two-year monitoring period adhesion to the concrete was good, and physical damage was not a problem. Changing color and contrast over the two-year period was an issue, however. Three out of the four products in the study exhibited noticeable color fading, and contrast with the adjacent surfaces decreased in two cases, due to the accumulation of dirt on the truncated dome products