Doing the math of ADA / CBC 11B residential parking

[Yikes]

Trying to interpret how to apply 11B-208.2.3.2 for additional accessible parking when you have parking ratios in excess of one space per dwelling unit.
Is the 2% additional based on:
(1) all the spaces left over after you provided one space for all units, or
(2) all the spaces left over after you provided the accessible stalls just for the accessible unit?

EXAMPLE: 200 public funded dwelling units, 300 resident parking spaces provided. (No guest or employee or non-resident spaces provided.)
5% mobility accessible units = 10 mobility units.
We know 208.2.3.1 will require 10 accessible spaces for the 10 mobility units. But how do you calculate the additional accessible spaces per 208.2.3.2 for the residents?

• Option 1: (300 spaces - (200 units x 1 space per unit)) x 2% = 2 additional accessible spaces. (10+2) = 12 accessible spaces out of 300.
• Option 2: (300 spaces - 10 accessible resident spaces) x 2% = 5.8 ~ round up to 6 additional accessible spaces. (10+6) = 16 accessible spaces out of 300.

Here's the code sections:

 

[wwhitney]

I would say option 1, as 200 of the spaces are "covered by Section 11B-208.2.3.1".

Cheers, Wayne

 

[mark handler]

Very difficult question, I agree with Wayne, you can make the case 208.2.3.1 covers all the parking on site.
BUT
that would be the case everywhere and you would never need the "option 2". I do believe option two is the intent of the code writers.

 

[mark handler]

Contact the Division of the State Architect, Access Compliance Division, (916) 322-8976

 

[wwhitney]

Option 2 is wrong, it makes zero sense and is not plausibly the intention.

In the example given, consider what happens as you transition from 200 spots, covered by only Section 11B-208.2.3.1, to 201 spots, where Section 11B-208.2.3.2 first comes into play.

Under Option 1, adding the 201st spot triggers the requirement for 2% of a spot to be accessible. The language in Section 11B-208.2.3.2 comes into play requiring "no fewer than one" of the additional spots to be accessible, so your 201st spot is accessible.

Under Option 2, Section 11B-208.2.3.2 now requires that 2% * 191 = 3.82 additional spots be accessible. So you add one spot, and not only does it have to accessible, you have to go back and make 2 or 3 or your earlier spots accessible? Moreover, the language about "no fewer than one" would basically never trigger.

Cheers, Wayne.

 

[mark handler]

the language about "no fewer than one" would basically never trigger.

Cheers, Wayne.

If 45 total parking spaces were required, 45 x .02 (2%)= O.9 spaces, need accessibility. 0.9 is less than 1.
statement triggered

 

[Yikes]

The crux of the issue is, what spaces are the ones that are already “…covered by Section 11B-208.2.3.1”?
Is it referring to only the accessible spaces scoped under that section (option 2), or is it referring to the 1:1 parking for every single unit (option1)?

 

[wwhitney]

The only difference between the two interpretations is what happens when you add the first parking spot beyond the number of dwelling units. Thereafter, both interpretations agree that 2% of the additional spots need to be accessible.

So all you need to decide is which of the two scenarios for the 201st spot in your example makes more sense: that Section 11B-298.2.3.2 is saying that the 201st spot has to be accessible, or that it is also saying that you must go back and switch more of your first 200 spots to being accessible?

The latter interpretation makes no sense.

Cheers, Wayne

 

[arwat23]

Per DSA's 2022 Advisory Manual:
Advisory 11B-208.2.3 Residential facilities. Sections 11B-208.2.3.1, 11B-208.2.3.2, and 11B-208.2.3.3 work in conjunction with each other and are to be used together to determine the correct number of accessible parking spaces. Where at least one parking space is provided for each dwelling unit, at least one accessible space is required for each mobility accessible unit provided(11B-208.2.3.1) and those spaces must be located on the shortest accessible route to the dwelling unit they serve (11B-208.3.2). If the total number of resident parking spaces is less than the total number of dwelling units, Table 11B-208.2 is used to determine the number of resident parking spaces required to be accessible, but providing one accessible space for each mobility accessible unit is advisable. When additional resident parking spaces are provided beyond one space per dwelling unit, Section 11B-208.2.3.2 requires at least 2%, but no fewer than one, of the resident parking spaces provided in excess of the one per unit total to also be accessible. These spaces must be dispersed among all types of resident parking, except where substantially equal or greater accessibility is provided in terms of distance from an accessible entrance, parking fee, and user convenience (Section 11B-208.3.2 Ex.). Parking for guests, employees, or other non-residents are subject to the scoping table at 11B-208.2.

In short, Option 1 is correct.