California ADA Curb Ramp Requirements: Slopes, Landings, and Warnings

California ADA curb ramp requirements come from two sources that apply at the same time: the federal Americans with Disabilities Act and the California Building Code, Title 24, Part 2, Chapter 11B. Where the two conflict, the stricter rule controls, and on several points California is stricter. A curb ramp that satisfies the ADA but misses a Chapter 11B detail still violates the law. The 2025 edition of the CBC took effect on January 1, 2026.¹

When a Curb Ramp Is Required

Federal regulations require curb ramps or other sloped areas at every intersection where a newly constructed or altered street has curbs or barriers to entry from a pedestrian walkway.² The obligation isn’t limited to new work. Any planned alteration to an existing sidewalk, street, or public facility triggers a requirement to install or upgrade non-compliant curb ramps within the project’s scope. Routine maintenance like repaving or replacing a sidewalk section pulls in any adjacent non-compliant ramps as well.

The Three Ramp Types

Chapter 11B recognizes three basic configurations, and the right one depends on sidewalk width, corner geometry, and the direction of crossings.

Perpendicular curb ramps run perpendicular to the curb line, dropping straight from the sidewalk to the street. Running slope is capped at 1:12, and flared sides at 1:10.³
Parallel curb ramps run along the direction of sidewalk travel, lowering the pedestrian down to street level. They require a 48-by-48-inch turning space at the bottom, sloped no more than 1:48 in any direction. Running slope of the ramp segments is capped at 1:12.³
Blended transitions connect the sidewalk to the street with a gradual slope and no defined ramp run. The maximum running slope is a gentler 1:20 (5%).³

Combining perpendicular and parallel elements is also allowed. Whichever type you use, the common requirements in CBC Section 11B-406.5 for width, cross slope, landings, and detectable warnings still apply.

Slopes, Widths, and the Gutter Transition

The running slope of a perpendicular or parallel ramp cannot exceed 1:12 (about 8.33%). The cross slope, measured perpendicular to the direction of travel, cannot exceed 1:48 (about 2%). Even a slight sideways tilt can cause a wheelchair to drift, so this tolerance is tight. The minimum clear width of the ramp run, not counting flared sides, must be at least 48 inches.³

Counter Slope at the Base

Where the bottom of the ramp meets the gutter or road surface, that adjoining surface cannot slope back upward more than 1:20 (5%) within 24 inches of the ramp. The transition itself must be flush, with no lip or vertical gap. This detail is one of the most commonly missed in the field, and a steep gutter pan at the base of an otherwise correct ramp creates a tipping hazard for wheelchair users.³

Grade Breaks

Grade breaks at the top and bottom of the ramp run must be perpendicular to the direction of travel. No grade break is allowed on the ramp surface itself or within turning spaces, and where two slopes meet at a grade break, the surfaces must be flush.³

Landings and Flared Sides

A flat landing is required at the top of every perpendicular curb ramp and blended transition. The landing must be at least 48 inches long and at least as wide as the ramp (flares excluded), with a slope no greater than 1:48 in any direction. This gives a wheelchair user space to stop and reorient before entering the ramp. Parallel ramps are exempt from this top landing requirement because their design already includes a level turning space at the bottom.³

Where the edge of a ramp sits along a pedestrian path, flared sides must be provided so pedestrians don’t trip on a sudden elevation change. Flares cannot be steeper than 1:10 (10%).³ If the ramp is positioned so pedestrians won’t walk across its sides, a returned curb (a vertical edge) can be used in place of a flare.

Detectable Warning Surfaces

These are the bumpy, brightly colored pads at the bottom of the ramp. They alert people with visual impairments, through both touch and contrast, that they’re about to step into a vehicular area. Every curb ramp and blended transition in California must have detectable warnings that comply with CBC Section 11B-705.³

Dome Dimensions

The truncated domes must have a base diameter between 0.9 and 0.92 inches and a height of 0.2 inches.⁴ The tolerances are narrow because the domes have to be detectable underfoot and with a cane without becoming a tripping hazard themselves. The warning surface must extend the full width of the ramp, flares excluded.

Color and Contrast

California is stricter than the federal ADA here. All detectable warning surfaces in the state must be yellow, approximating Federal Standard color 33538. The federal rule has no color mandate at all. On top of the yellow requirement, the surface must provide at least 70% visual contrast with the adjacent walking surface. If 70% contrast can’t be achieved, a one-inch-wide contrasting border must separate the warning surface from the surrounding pavement.⁴

When replacing less than 20% of existing detectable warnings at a single location, the replacement panels can match the existing installation’s code-era specifications rather than meeting current standards.⁵

Placement at the Intersection

The code requires a curb ramp or blended transition at each pedestrian street crossing. At a typical corner serving two crosswalks, that means two separate ramps, each aligned with its crosswalk. The ramp body (flares excluded) must be wholly contained within the crosswalk markings. Curb ramps and their flared sides cannot project into vehicular lanes, parking spaces, or parking access aisles.³

Diagonal Ramps

A diagonal (corner-type) ramp serves two crosswalks from a single point at the apex of the corner. Chapter 11B doesn’t outright ban them, but they’re disfavored because they point wheelchair users into the center of the intersection rather than into either crosswalk. When one is used, the bottom must have at least 48 inches of clear space outside active traffic lanes. If the crossing is marked, that 48-inch clear space must fall within the markings. Diagonal ramps with flared sides also require a 24-inch minimum curb segment on each side within the marked crossing.⁶ Most jurisdictions treat them as a last resort when physical constraints prevent two separate ramps.

The 20% Path-of-Travel Rule

When an existing facility is altered, the primary path of travel to the altered area must also be brought into compliance, and curb ramps are part of that path. The cost of these accessibility upgrades is capped at 20% of the adjusted construction cost of the main alteration project. If full compliance would cost more than 20%, you still have to spend up to that threshold and achieve as much compliance as possible within it.⁷

For larger projects that exceed a state-set valuation threshold, the enforcing agency can evaluate whether full compliance would create an unreasonable hardship. Even then, spending cannot fall below 20% of the adjusted construction cost. The practical effect is that a business remodeling an interior space may need to allocate a real portion of its budget to exterior work like curb ramps, accessible parking, and route upgrades.

When Full Compliance Isn’t Possible

Not every site can hit every number, and the code accounts for that through two distinct standards.

Structural Impracticability

This applies to new construction and is read narrowly. Full compliance is considered structurally impracticable only in rare cases where the unique characteristics of the terrain prevent incorporating accessibility features. Even then, every portion of the facility that can be made accessible must be. If wheelchair accessibility is physically impossible, the facility must still be accessible to people with other disabilities, such as those using crutches or with sensory impairments.⁸

Technical Infeasibility

This applies only to alterations of existing buildings, never to new construction. It covers situations where full compliance would require removing a load-bearing structural member, or where existing physical constraints make compliant modifications impossible. When the standard is met, the alteration must still provide accessibility to the maximum extent feasible, and every element being altered that can be made accessible has to be.⁹

Claiming either exception requires documentation: the specific physical barriers, the steps taken to achieve maximum compliance, and any programmatic alternatives. Inspectors and courts read these claims skeptically. Cost alone doesn’t qualify; the barrier has to be a genuine physical constraint.

What Non-Compliance Costs

Under the Unruh Civil Rights Act, a person denied access to a business establishment can recover up to three times their actual damages, with a floor of $4,000 per offense.¹⁰ Because each visit where a barrier is encountered can be a separate offense, exposure adds up fast. Attorney’s fees are recoverable, which usually means the legal costs dwarf the statutory damages.

California Civil Code Section 55.56 adds some guardrails. A plaintiff can only recover statutory damages if they personally encountered the violation or were actually deterred from visiting the property on a particular occasion. The statute also reduces minimum damages for businesses that act quickly: fix all violations within 60 days of being served and have had a Certified Access Specialist inspection, and minimum statutory damages drop to $1,000 per offense. Small businesses with 25 or fewer employees and less than $3.5 million in average annual gross receipts that correct violations within 30 days qualify for a $2,000 minimum instead of $4,000.¹¹

For the person building or inspecting a ramp, the math usually comes out the same way: getting the slopes, the landing, the gutter transition, and the yellow dome pad right the first time is cheaper than any of the alternatives.

1
California Department of General Services. 2025 Part 2 Chapter 11B Accessibility to Public Buildings
2
eCFR. 28 CFR 35.151 – New Construction and Alterations
3
UpCodes. California Building Code 11B-406 Curb Ramps, Blended Transitions and Islands
4
UpCodes. California Building Code 11B-705 Detectable Warnings and Detectable Directional Texture
5
Caltrans. Detectable Warning Surface Authorization Criteria
6
UpCodes. California Building Code Chapter 11B Accessibility to Public Buildings
7
UpCodes. California Building Code 11B-202.4 Path of Travel Requirements in Alterations, Additions and Structural Repairs
8
UpCodes. Exception for Structural Impracticability
9
Disability Access and Compliance. Technical Infeasibility Exemptions
10
California Civil Rights Department. Discrimination at Business Establishments
11
California Legislative Information. California Civil Code 55.56