ADA Curb Ramps vs Standard Curb: Requirements

ADA curb ramps and standard curbs aren't alternatives — they're paired elements of a compliant parking-lot perimeter. Standard curb (typically 6-inch face barrier curb) defines the pavement edge and stops vehicles. ADA curb ramps interrupt that curb at every accessible-route crossing so wheelchair, walker, and stroller users can move between the parking lot and the sidewalk or building entrance. The Americans with Disabilities Act (ADA Standards for Accessible Design Section 405) governs ramp geometry, and the U.S. Access Board (Public Right-of-Way Accessibility Guidelines, PROWAG) provides the right-of-way detail that most jurisdictions adopt by reference.

What follows: the geometric and regulatory distinction, where ramps are required, the four ramp types you can specify, and the cost picture.

Quick Verdict: ADA Curb Ramp vs Standard Curb

Current Market Reality

ADA curb-ramp retrofits are one of the highest-leverage compliance items for commercial property managers in 2026 because Department of Justice settlements for non-compliant ramps routinely run $25,000 to $75,000 per site plus attorney fees. The cost of installing compliant ramps is a fraction of the litigation exposure.

What Is a Standard Curb?

Standard barrier curb is a 6 to 8 inch face concrete element poured along the parking-lot perimeter to define the pavement edge, channel drainage, and stop vehicles at parking-aisle speeds. It is a continuous structural element with expansion joints every 10 to 15 feet per Oregon Standard Specification 00759. For complete spec detail see our concrete curb buyer's guide.

What Is an ADA Curb Ramp?

An ADA curb ramp is a sloped concrete transition that connects a lower elevation (parking-lot pavement) to a higher elevation (sidewalk or accessible route) at a slope and width that allows wheelchair, walker, and stroller access. ADA Standards Section 405 lists four common types:

Perpendicular ramp: The most common form. The ramp runs perpendicular to the curb line, descending from the sidewalk to the pavement at 1:12 maximum slope. Flares on each side at 1:10 maximum slope create a transition between the ramp and the adjacent curb.

Parallel ramp: Used where space behind the curb is too narrow for a perpendicular ramp. The ramp runs parallel to the curb line, with a 36 by 36 inch landing at the bottom. This is common in dense urban settings where buildings sit close to the back-of-curb.

Combination ramp: A perpendicular ramp at the curb face plus a parallel ramp leading to it. Used at corner locations where the elevation change exceeds what a single perpendicular ramp can handle.

Built-up ramp: Less common; used where the sidewalk grade cannot be lowered, so the ramp is built up from the parking-lot pavement to meet the existing sidewalk elevation.

The PROWAG Guidelines Section R304 provide the controlling geometric detail; most Oregon jurisdictions adopt PROWAG by reference.

Where Are Curb Ramps Required?

ADA curb ramps are required at every location where an accessible route crosses a curb. In a typical commercial parking lot, this means:

• Every accessible parking space must connect to the building entrance via an accessible route. The route crosses the curb at the head of the accessible space — that crossing requires a ramp.
• Every public sidewalk corner that abuts the parking lot. If the lot connects to a public sidewalk, the corner ramps are required by both ADA and PROWAG.
• Every accessible route between buildings on a campus. Multi-building sites often have walking routes between structures that cross parking-lot perimeter curbs.
• Loading zones designated as accessible. ADA Section 503 requires accessible loading zones to connect to accessible routes via ramps where curb crossings occur.

For broader compliance context see our ADA parking lot striping guide.

Detectable Warning Surfaces

ADA Section 705 and PROWAG R305 both require a detectable warning surface at the base of every curb ramp. The surface is a 24-inch deep band of truncated domes contrasting visually with the surrounding pavement. The domes are 0.9 inches diameter, 0.2 inches tall, spaced 1.6 to 2.4 inches on-center.

Three installation methods:

Cast-in-place panels: A removable form is set in the wet concrete, creating the truncated-dome pattern in the cured surface. The truncated domes are integral to the concrete — no replaceable surface.

Surface-applied panels: Manufactured polymer or composite panels glued to a cured concrete surface. These are the standard retrofit method on existing ramps.

Pre-cast panels: Concrete panels with the truncated-dome pattern cast in at a precast plant. Embedded in the wet ramp pour during installation.

Cost Comparison

Industry Baseline Range, single ramp

For ramp-specific cost detail see ADA curb ramp cost installation and for ramp selection see best curb ramp for ADA compliance. Our asphalt paving services crew handles parking-lot ADA upgrades alongside other site work.

Get Your Site ADA-Compliant

Standard curb and ADA ramps are a pair, not a choice. A compliant parking lot perimeter has continuous standard curb interrupted by code-compliant ramps at every accessible-route crossing. We've handled ramp upgrades on dozens of Oregon commercial sites — including a 16-ramp retrofit at a Salem state-government complex in February 2026 — and we walk every site to identify the required ramp count before quoting.

Get a custom quote for your ADA compliance work, or schedule a site walk to map every required ramp location.