ADA Compliant Sidewalks and Curb Ramps

By Brian Adams, PCM Concrete Division Manager | October 17, 2013

ADA lawsuits are on the rise! In the last
5 years, ADA litigation has risen 90%.
Are you at risk?


The facts:

  • The Americans with Disabilities Act (“ADA”) was signed into law on July 26,1990, and became effective January 26, 1992.
  • On September 15, 2010 revised regulations were made.

In this blog we answer the following questions:

  • What exactly is a curb ramp?
  • Is my curb ramp ADA compliant?
  • Can my property be grandfathered in?

What is a curb ramp?

We are all familiar with the ramps that cut through a curb and those that are built up to meet a curb. Why are they there? Curb ramps provide an accessible route that people with disabilities can use to safely transition from a road to a curbed sidewalk and vice versa.

The most common type of curb ramp is the perpendicular curb ramp, which intersects the curb at a 90-degree angle. The different parts of the ramp are labeled in the illustration below.

perpendicular curb ramp

Parts of a perpendicular curb ramp. Diagram courtesy of the ADA.

  • Ramp/Ramp Run– A sloped section of the sidewalk that allows people with wheelchairs to travel up and down when transitioning between the street and the sidewalk.
  • Transitions– A gradual incline between the ramp and the sidewalk, gutter and street located at the top and bottom of the ramp run.
  • Flared Sides/Flares– Sloped transitions between the ramp and the surrounding sidewalk designed to prevent pedestrians from tripping.

Calculating slope:

Flash back to high school algebra for a moment. Slope = rise ÷ run. (Also shown as rise:run). Do you remember this formula? Well, when you learn the slope of a curb ramp must be 1:12, this means that 12 inches of ramp is needed for every inch the ramp rises. Simple, right? Algebra class dismissed.

Is my curb ramp ADA compliant?

Inspect your ramp with this compliance checklist from the ADA:

  • For curb ramps constructed after January 26, 1992 (post-ADA), the slope must be 8.33% (1:12) or less.
  • For curb ramps constructed before January 26, 1992 (pre-ADA), including those that have since been altered, the running slope must generally be 8.33% or less. However, ramp runs with greater slopes are allowed for pre-ADA curb ramps in the two following instances where space limitations are a factor:The cross slope of the ramp run itself may not exceed 2% (1:50). (On a curb ramp, the cross slope is the slope perpendicular to the direction of pedestrian travel on the ramp run.)
    • The ramp run may have a running slope of up to 10% (1:10) if the rise is no more than 6 inches.
    • The ramp run may have a running slope of up to 12.5% (1:8) if the rise is no more than 3 inches.
  • The ramp run must be at least 36 inches wide, not including the flared sides.
  • The ramp run must have detectable warnings – i.e., those dome-shaped bumps otherwise known as “truncated domes” – that extend the full width and cover the first 2 feet of the ramp.
  • Transitions from the ramp to the walkway, gutter, and street must be flush (level) and free of abrupt level changes.
  • The gutter must have a slope of no more than 5% (1:20) toward the ramp.

ADA compliant curb ramp

ADA compliant curb ramp. Diagram courtesy of the Federal Highway Administration.

What are the requirements for flared sides?

Curb ramps must have flared sides if people are required to walk across them. The slope requirements for the flared sides depend on the width of the sidewalk at the top of the ramp. If the width of the sidewalk at the top of the ramp is less than 48 inches, then the slope of the flared sides must be no more than 8.33%. If the width of the sidewalk at the top of the ramp is 48 inches or more, then the flared sides may slope up to a maximum of 10%.

Can my property be grandfathered in?

It depends. If your property pre-dates the ADA statute (January 26, 1992), and the property has not gone through any significant renovations (determined on a case-by-case basis), then you may be “grandfathered in.” However, there can still be considerations of “reasonable accommodation” and “readily achievable barrier removal” under the ADA that could demand you make modifications to existing structures and make existing buildings “accessible” to the disabled.

On the other hand, if your property has undergone substantial alterations or renovations, the ADA requires alterations be made when it is “readily achievable” to do so. Readily achievable has been defined as “easily accomplishable without much difficulty or expense.”

Interested in learning about Parking Lot ADA guidelines?
Check out our blog
Parking Lot ADA Guidelines: What You Need to Know.

If you have any specific questions regarding your property
and these ADA requirements please feel free to contact
PCM Services at 1-301-595-3700.