ADA/ABA Key Dimensions Quick Reference
This cheat sheet covers the most commonly tested ADA/ABA accessibility dimensions on the ARE 5.0 PDD exam. Memorize these numbers-they appear frequently. For a deeper dive, see the ADA Accessibility topic guide.
Accessible Route Requirements
| Element | Minimum Dimension | Notes |
|---|
| Accessible route width | 36" clear | 44" in healthcare facilities |
| Passing space | 60" x 60" | Required every 200' if route < 60" wide |
| Headroom clearance | 80" min | Along entire accessible route |
| Ground/floor surface | Firm, stable, slip-resistant | 1/4" max change in level without treatment |
| Carpet pile height | 1/2" max | Must be securely attached |
Door Requirements
| Element | Dimension |
|---|
| Clear opening width | 32" min (standard door) |
| Maneuvering clearance (pull side, front approach) | 60" depth, 18" latch side |
| Maneuvering clearance (push side, front approach) | 48" depth |
| Threshold height | 1/2" max (3/4" for sliding doors) |
| Door hardware height | 34"–48" AFF |
| Closing speed (non-fire door) | 5 seconds min from 90° to 12° |
| Opening force (interior, non-fire) | 5 lbs max |
Ramp Requirements
| Element | Requirement |
|---|
| Maximum running slope | 1:12 (8.33%) |
| Maximum cross slope | 1:48 (2%) |
| Minimum clear width | 36" |
| Maximum rise per run | 30" |
| Landing length (top and bottom) | 60" min |
| Handrails required | Both sides when rise > 6" |
| Handrail height | 34"–38" |
| Handrail extension | 12" beyond top/bottom |
Restroom Clearances
| Element | Dimension |
|---|
| Wheelchair-accessible stall | 60" wide x 59" deep (wall-mounted WC) or 60" x 56" (floor-mounted) |
| Toilet centerline from side wall | 16"–18" |
| Toilet seat height | 17"–19" AFF |
| Grab bar (side wall) | 42" long, 12" from rear wall |
| Grab bar (rear wall) | 36" long |
| Grab bar height | 33"–36" AFF |
| Lavatory knee clearance | 27" high, 30" wide, 11"–25" deep |
| Mirror bottom edge (above counter) | 40" max AFF |
Reach Ranges
| Reach Type | Range |
|---|
| Forward reach (unobstructed) | 15"–48" AFF |
| Forward reach (over 20"–25" obstruction) | 44" max high |
| Side reach (unobstructed) | 15"–48" AFF |
| Side reach (over 10" obstruction) | 46" max high |
Parking Requirements
| Total Spaces | Accessible Spaces Required |
|---|
| 1–25 | 1 |
| 26–50 | 2 |
| 51–75 | 3 |
| 76–100 | 4 |
| 101–150 | 5 |
| 151–200 | 6 |
| 201–300 | 7 |
| 301–400 | 8 |
| 401–500 | 9 |
| 501–1000 | 2% of total |
| 1001+ | 20 + 1 per 100 over 1000 |
- Van-accessible spaces: 1 per every 6 accessible spaces (or fraction)
- Standard accessible space: 96" wide + 60" access aisle
- Van-accessible space: 132" wide + 60" access aisle (or 96" + 96" aisle)
Counter and Service Heights
| Element | Height |
|---|
| Sales/service counter | 36" max for 36" min length portion |
| Dining/work surface | 28"–34" AFF |
| Drinking fountain (wheelchair) | 36" max spout height |
| Drinking fountain (standing) | 38"–43" spout height |
| Light switches and outlets | 15"–48" AFF |
Practice these dimensions with PDD flashcards and test yourself with a PDD mini exam. Create a free account to track your progress.