ADA Parking Space Requirements: How Many You Need

The One Number Every Oregon Lot Owner Should Know

Almost every conversation about accessible parking comes down to a single question: how many spaces do I actually need? The full requirements around dimensions, signage, and slope matter, and our ADA parking compliance guide for Oregon walks through all of them. This page focuses on the math: the count.

The number is not arbitrary. It comes from a fixed table in the 2010 ADA Standards for Accessible Design, and it scales with the total capacity of your lot. Get the count wrong by even one space and you have a violation that a plaintiff's attorney can spot from the parking lot without leaving their car.

The 2010 ADA Count Table

The federal table works in tiers. Below 1,000 spaces, the requirement climbs by one accessible space roughly every 25 total spaces. Above 1,000, it switches to a percentage-plus-formula.

Total Parking Spaces	Minimum Accessible Spaces
1 to 25	1
26 to 50	2
51 to 75	3
76 to 100	4
101 to 150	5
151 to 200	6
201 to 300	7
301 to 400	8
401 to 500	9
501 to 1,000	2% of total
1,001 and over	20, plus 1 for each 100 over 1,000

A 25-space corner lot needs one accessible space. A 120-space strip center needs five. An 800-space mall lot needs 16 (2 percent of 800). A 1,400-space regional center needs 24 (20 base, plus four for the 400 spaces over 1,000).

Count the spaces actually provided, not the spaces you wish you had. Striped overflow, employee rows, and reserved spots all count toward the total unless they are genuinely closed to the public and the people who park there.

The Van Ratio: 1 in 6

Counting total accessible spaces is only half the job. Of those accessible spaces, at least one in every six (rounded up) must be van-accessible. Van-accessible spaces have a wider access aisle so a side-deploying wheelchair lift has room to operate.

Accessible Spaces	Minimum Van-Accessible
1 to 6	1
7 to 12	2
13 to 18	3
19 to 24	4

So a lot with one accessible space still needs that single space to be van-accessible. A lot with five accessible spaces needs one van space. A lot with seven needs two. The ratio rounds up every time, which trips up a lot of older layouts that assumed one van space was enough no matter how big the lot grew. For the dimensional details on those wider stalls, see our breakdown of van-accessible spaces in Oregon.

Where Oregon Adds Its Own Layer

Federal ADA sets the floor. Oregon law, primarily ORS 447.233 and the Oregon Structural Specialty Code (Chapter 11), can require equal or stricter treatment in certain situations and adds Oregon-specific signage rules on top of the count. The accessible-space counts themselves generally track the federal table, but Oregon enforces them through state building officials and adds requirements like the supplemental fine plate on signage that many other states do not have.

The practical takeaway: meeting the federal count is necessary but not always sufficient. Your local building department in Marion, Lane, Multnomah, or any Oregon county is the entity that signs off when you alter or build a lot, and they apply the state code. The full Oregon-specific picture lives in our Oregon ADA parking requirements page.

Special-Use Counts That Override the Standard Table

A handful of facility types do not use the standard table at all:

• Outpatient medical facilities must provide accessible spaces equal to 10 percent of total spaces.
• Rehabilitation and outpatient physical therapy facilities must provide 20 percent.
• Hospitals with outpatient units apply the higher ratio to the portion of the lot serving those units.

If you operate a clinic, a dialysis center, or a physical therapy practice, do not use the 1-in-25 table. The percentage rule produces a much higher count, and missing it is one of the more expensive compliance errors because the gap is large.

Counting Across Multiple Lots and Entrances

When a single property has several separate parking areas, the ADA generally lets you count each lot on its own, but the accessible spaces have to be distributed so that each building entrance is served by the shortest accessible route. You cannot pile all the accessible spaces into one corner of one lot and call the campus compliant.

For multi-tenant retail and shopping centers, accessible spaces should be spread across the frontage so a visitor to any storefront has a nearby accessible space. Concentrating them defeats the purpose and invites complaints even when the raw count is technically met.

Why the Count Is the First Thing an Auditor Checks

A formal review starts with the easy, objective measurements, and space count is the easiest of all. An auditor walks the lot, totals the spaces, totals the accessible spaces, checks the van ratio, and compares against the table. It takes minutes and requires no judgment calls. That is exactly why it is also the first thing a serial plaintiff checks. Our ADA compliance audit process page covers what a full walk-through includes beyond the count.

If your count is short, no amount of perfect signage or fresh paint elsewhere fixes the violation. The number has to be right first.

Getting the Count Right During a Restripe

The good news is that count problems are usually fixable during a routine restripe, because adding an accessible space is mostly a layout decision. The catch is that accessible spaces and their aisles are wider than standard spaces, so adding them can reduce your total space count, which can in turn change which tier of the table you land in. A contractor who measures the lot and runs the layout against the table before painting avoids that circular problem.

When Cojo lays out a lot, the accessible-space count is calculated against the actual measured capacity, the van ratio is applied, and the placement is checked against entrance routes before any paint hits the asphalt. That is the difference between a lot that passes and a lot that merely looks finished.