Truncated Domes

The requirements of the Accessible Public Rights-of-Way (R304 Detectable Warning Surfaces) requires you to have truncated domes wherever there is a meeting of a sidewalk or walkway and a street accessible by motorized vehicles.

The rule states that there must be a detectable warning system for all persons who have a visual disability so they know when the transition from foot traffic to motorized traffic occurs.  They must be detectible both visually (dark on light or light on dark) and tactilely, and must comply with specific measurements. These measurements include:

  • Base diameter of 0.9 inches to 1.4 inches
  • The top diameter must be between 50 and 65 percent of the base diameter
  • The height must be 0.2 inches

There must be tactile paving extending 24 inches in the direction of travel and must include the full width of the curb, landing, or blended transition.  This is to ensure that any visually impaired person using the walkway will have plenty of notice before the end of the curb.  It also provides safety for sighted persons due to the contrasting colors.

If you have any questions or would like more information on using truncated domes to comply with the Public Rights of Way and the Americans with Disabilities Act, please call 800-372-0519 for assistance.