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The Ins and Outs of Detectable Warning Systems

If you are designing ADA compliant flooring for your business or contracting with local government for work on public rights-of-way you can’t afford to not know the ins and outs of detectable warning systems.

The Americans with Disabilities Act (ADA) has led to federal regulations that require these warning aids follow specific guidelines for the height, alignment, geometric shape, and spacing of raised tactile profiles – truncated domes.

Get Familiar with the Government Regulations

To get started, check out the United States Access Board. You will find there everything you need to familiarize yourself with both the American with Disabilities Act and how you can you ensure your projects comply with its requirements.

Things addressed here include:

  • Alterations and Additions to Existing Facilities – this includes new construction guidelines and alterations to existing property.
  • Pedestrian Crossings – coverers access to overpasses, underpasses, and others.
  • Detectable Warning Surfaces
  • Doors, Doorways, and Gate

Detectable Warning Surfaces

Also called tactile warning surfaces, these are detectable warning systems built within or applied to travel and walkways. Their purpose is to provide sensory signals to both visually and non-visually impaired pedestrians so they can transition across a sudden change in walking surface elevation or cross a potentially dangerous vehicular way.

These are required by the ADA on:

  • Handicap Ramps
  • Curb Ramps
  • Exterior Paths of Travel
  • Platform edges on rail and bus stations
  • Change in elevation along a public path of travel
  • At retail entry and exit points that connect to parking areas or vehicular ways

When Building Curbs

The ADA had specific guidelines for public and private walkways as well as public curbing.

ADA compliant specifications for a curb ramp include:

  • Slope – curb ramps built after January 26, 1992 must be 8.33% or less.
  • Width – must be a minimum of 36 inches wide.
  • Detectable warnings – dome-shaped bumps are required to extend the ramp’s full depth and width.
  • Transitions – must be level with the walkway, street, or gutter.
  • Location – anywhere a pedestrian path or sidewalk meets a curb must have ADA compliant curb ramps.


There are plenty of great, free resources available to help bring you up to speed on detectable warning systems. The American Public Works Association offers some great advice in the APW Reporter.

“It’s not enough to simply slap a curb ramp on the end of a sidewalk and call it a day … When undertaking any ADA project it’s important for the entire team to keep compliance as the number one goal.”

When planning a new addition to your private business or taking aim at that big contract at city hall, start right so you can finish right.

Ivy Skye Marshall: Ivy, a social justice reporter, covers human rights issues, social movements, and stories of community resilience.