Curb Ramp and Detectable Warning Guide

How to review curb ramps, landings, flares, counter slopes, transitions, and truncated dome detectable warnings on site and civil drawings.

Code Compliance

Curb ramps connect accessible routes across changes in curb elevation. They look simple on site plans, but they are one of the easiest details to fail because slope, cross slope, landings, flares, drainage, and detectable warning placement all have to work together.

The 2010 ADA Standards require curb ramps on accessible routes to comply with curb ramp and ramp provisions, including a maximum curb ramp running slope of 1:12, maximum adjacent counter slope of 1:20, and top landings at least as wide as the ramp and 36 inches minimum in clear length.

Plan Review Checklist

Review curb ramps on the civil plans, grading plans, landscape plans, and architectural accessibility diagrams. The most reliable review starts by tracing the full accessible route instead of checking each ramp in isolation.

Ramp run slope, cross slope, and counter slope.
Top landing size and location.
Bottom clear space outside active traffic lanes where required.
Flare slopes where pedestrians can cross the flares.
Drainage that does not pond at the bottom of the ramp.
Detectable warning surface size, contrast, and location.

Detectable Warnings

Detectable warnings use truncated domes to alert pedestrians who are blind or have low vision that they are entering a vehicular way or platform edge. The ADA technical criteria define dome size, dome spacing, and visual contrast.

Helonic can help flag drawing conditions where ramps, landings, sidewalks, and road grades appear inconsistent, giving the project team a cleaner path to accessibility review.

Frequently Asked Questions

What slopes govern a compliant curb ramp?

The 2010 ADA Standards set a maximum curb ramp running slope of 1:12, a maximum cross slope of 1:48, and a maximum adjacent counter slope in the gutter of 1:20. Combined ramp and counter slopes that are too steep create a transition users cannot negotiate. These should be checked on the grading plan spot elevations, not assumed from plan geometry.

What are the top landing requirements?

A top landing has to be at least as wide as the ramp and provide a clear length of at least 36 inches at the top, with a slope no steeper than 1:48. Without an adequate landing, a wheelchair user cannot maneuver at the top of the ramp. The landing size should be confirmed against the surrounding grades.

What do detectable warnings do and how are they sized?

Truncated dome detectable warnings alert pedestrians who are blind or have low vision that they are entering a vehicular way. The ADA technical criteria define dome base and top diameter, dome spacing, and a contrasting color. The surface depth and placement at the back of curb should match those criteria on the detail.

Why review the full accessible route instead of each ramp?

Ramps connect across a continuous route, so checking each ramp in isolation misses running slope, cross slope, and drainage problems that accumulate along the path. A compliant ramp is useless if the route to it exceeds slope limits. Tracing the whole route on the civil and landscape plans is the reliable method.

How does drainage affect curb ramp compliance?

Water that ponds at the bottom of a ramp creates a hazard and can indicate a counter slope that traps runoff. Grading has to move water away from the ramp landing and gutter transition. The drainage pattern should be checked against the ramp spot elevations.

MG

Manas Gandhi

Co-founder & CTO, Helonic

Manas is the co-founder and CTO of Helonic, where he leads engineering and AI research for construction drawing analysis. He works directly with structural, MEP, civil, and fire protection engineers to translate the way they review drawings into AI systems that flag the issues that actually matter in the field. Before Helonic, he built machine learning pipelines for technical document understanding and has spent the last several years interviewing licensed design engineers and discipline leads to ground product decisions in real practice rather than industry assumptions.

Areas of focus

AI for technical document understanding
Cross-discipline coordination workflows
Code compliance automation (IBC, NEC, NFPA, IPC, IMC, ASCE)
Structural and MEP drawing review systems

How this page was researched: Curb ramp and detectable warning review points were checked against the 2010 ADA Standards for Accessible Design and ICC A117.1, with running slope, counter slope, landing, and truncated dome criteria taken directly from those provisions. Examples reflect the accessibility conflicts Helonic most often flags when comparing civil, grading, and landscape drawings.

Last reviewed by Manas Gandhi · May 2026

Keep exploring

Related guides, comparisons, and features for coordination teams.

ADA Accessibility Guide

Core accessibility concepts for construction drawing review.

Accessibility Checking

Helonic review workflows for accessibility conflicts.

Catch Accessibility Conflicts in the Drawings

Helonic checks accessibility-related drawing conditions so teams can resolve curb ramp, route, slope, and landing issues before concrete is placed.