Maintaining level, accessible parking spaces

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  Q: Is the 2% cross slope requirement for just the linear direction of a parking space? I hear several different opinions from my engineers and contractors.
Alex, Washington State

    Editor's Note: ADA standards and accessibility guidelines clearly state that no greater than a 2% cross slope for parking spaces should be applied in all directions:

    1990/1994 ADAAG Section 4.6.3* Parking Spaces. “... Parking spaces and access aisles shall be level with surface slopes not exceeding 1:50 (2%) in all directions.”

    2010 ADA Section 502.4 Floor or Ground Surfaces. “Parking spaces and access aisles serving them shall comply with 302. Access aisles shall be at the same level as the parking spaces they serve. Changes in level are not permitted. EXCEPTION: Slopes not steeper than 1:48 shall be permitted.” (The exception allows sufficient slope for drainage. Built-up curb ramps are not permitted to project into access aisles and parking spaces because they would create slopes greater than 1:48.)

    Advisory for 502.4 Floor or Ground Surfaces. “Access aisles are required to be nearly level in all directions to provide a surface for wheelchair transfer to and from vehicles.”

A: Steep slopes in any direction threaten the safety and ability of the user who’s trying to control a wheelchair while exiting a car and then closing the door.

Alex, I am so glad that your question includes the fact that the professionals you trust are giving you different opinions. I can’t tell you how often engineers or construction/parking lot layout plans place the designated ADA parking space too close to a building that has a steep slope approach.

The problem is, they haven’t considered that for a wheelchair user trying to exit or enter a vehicle, extreme slopes are dangerous. I understand that your professionals might feel torn between two different requirements (i.e., convenient parking vs. maintaining a level surface). But the level surface must be the priority.

Please do everything possible to plan accessible parking spaces carefully and with landscaping that will fulfill ADA requirements for both close and level parking locations.

I have an exercise for anybody who feels up to the challenge:

    1. Place a folding chair equipped with wheels in the back seat of your car.

    2. Next, park in a sloped location and remove the chair while you remain sitting in your driver’s seat.

    3. Place the chair on the ground next to your car door (the chair may start rolling away due to the unlevel surface).

    4. Meanwhile, try to transfer from the vehicle to the chair without using your legs. Imagine they have no strength.

How are you doing? By now, this activity should drive home why a level parking space and adjacent access aisle is imperative in parking lot designs.

If you didn’t try my exercise above, examine the graphic below that depicts a driver using a manual chair. This illustration should help you understand the difficulty in trying to control the wheelchair on a severe slope.

As a wheelchair user, I have fallen off my ramp on a sloped parking space too many times, especially in inclement weather. I have ruined clothes and injured my knees — but I’m lucky. At least I can crawl, unlike paraplegics or quadriplegics.


Take a look at the parking lot pictures to the left, taken by yours truly. The slope in the top picture is severe and there are not enough access aisles in the left picture. I run across these situations often. Improperly designed parking spaces are among my biggest pet peeves, so I will address the different issues related to accessible parking over the coming months.





This Illustration can be found in the Uniform Federal Accessibility Standards (UFAS) retrofit manual.


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April 19, 2012

A number of factors should be considered when designing or constructing parking facilities such as the existing terrain, etc. A simple solution when designing grades for parking lots that include ADA parking spaces & access aisles, is to use a maximum slope of 1.4% along the width and the same 1.4% along the length of the parking spaces. This ensures positive drainage while maintaining the 2% slope in the diagonal direction.

Posted By: torrken | Time: 3:32:12.863 PM

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April 19, 2012

Here the problem, Read the editor note: max 2% cross slope and then in any direction. Per ADA cross slope is define as perp. to path of travel, not all direction. Is max 2% absolute and 2.01% is no good. so what define the max 2%, a expansion ridge for the 1/2" would be greater than 2%. Since the DOJ are the one whom defend ADA (fed). They need to come up with clear guide lines. A sidewalk maybe at 5% slope with a 2% cross. note the max slope in all direction will greather than 5%. also these pub. are great, however the City inspector has his own standard and they are above the law, if you want to get your project pass.

Posted By: Fillmore | Time: 10:36:43.69 PM



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About the Blogger

Michele Ohmes

thumbnail image Michele S. Ohmes is an Americans with Disabilities Act specialist and wheelchair user 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.