Consultant Michele Ohmes answers your Americans with Disabilities Act (ADA) questions.

Q: Is the 2% maximum slope for parking spaces and access aisles only for the cross slope or for all directions?

A: Boy, have you hit on a pet peeve of mine!

The law's original language, as well as the 1994 and 2010 updates, clearly states the slope is not to exceed 2% -1:50 - in all directions. (There's only one exception: Slopes no steeper than 1:48 shall be permitted.)

Yet I can't tell you how much steep slopes affect my ability to enter my vehicle. In bad weather I've slipped off my ramp or lift; I have no idea how a manual chair user is able to overcome some of the slopes we're forced to use at "accessible" locations.

As for access aisles, the 2010 standards' Advisory 502.4 Floor or Ground Surfaces stipulates they're to be level with the parking spaces they serve. No exception.

While we're on the subject of parking, let's look at changes brought on by the 2010 standards.


The new van-to-regular-space ratio is 1:6 instead of 1:8.

One in every six accessible spaces must be served by an aisle at least 96 inches wide.

Everything else is the same: Van-accessible spaces must be designated as such and can be grouped together, such as on a single level in a garage or single aisle in a lot.


The difference between car and van spaces used to be width of the access aisle, with the Universal Design approach of the 60-inch-wide access aisle and a 132-inch-wide parking space accepted as an exception. Now the Universal Design approach is the first choice for a van space.

According to the updated standards, car parking spaces must be at least 96 inches wide and van parking spaces at least 132 inches wide (see top image). Spaces must be marked to define widths and have an adjacent access aisle. (Exception: Van spaces can be 96 inches wide when the access aisle is also 96 inches wide.)

Another issue that's usually ignored is the overall accessibility of the route from parking space to building entrance.

All too often design teams try to place accessible parking at one side of the facility with a curb ramp at the end of a walk. This requires the wheelchair user to travel a longer distance and navigate sidewalk protrusions such as sale items, newsstands, poles, etc. (The worst offenders are convenient/gas stores and strip malls.) A wheelchair user can't just step off onto the parking lot and back up onto the walk to pass an obstruction. We have to wait for assistance, which often doesn't come.

Mark crossings to enhance pedestrian safety and, when possible, construct accessible routes to pass in front of parked vehicles (see bottom image).

Remember that for every action there is a reaction. Every time a poorly thought-out layout is designed, those of us with disabilities - especially wheelchair users - are put in jeopardy and at times can't even use the facility. Think twice and seek assistance for the real users.

- Michele S. Ohmes (

) is an ADA specialist who works with public works departments, facility managers, and contractors. Her design manual, ADA and Accessibility: Let's Get Practical, is available on CD-ROM through the American Public Works Association's Web site. Author's note: Michele & Associates does not render legal advice and has no enforcement authority regarding the ADA or other federal disability-rights legislation.