Are truncated domes allowed in an accessible parking access aisle?

[Yikes]

ADA/CBC 11B-502.4 for accessible parking stall access aisles says: "Changes in level are not permitted. Exception: slopes not steeper than 1:48 shall be permitted."

Questions:

1. Are truncated domes in a detectable warning system per ADA / CBC 11B-705 allowed in the striped access aisle? Or do they constitute a "change in level" that is not allowed? Note that the elevation difference is less than 0.25".



2. If a dome that is 0.18" high is NOT allowed, then what are the allowable construction tolerances (surface texture) on an accessible stall and access aisle?

 

[Paul Sweet]

I've never seen truncated domes in a parking lot. They are usually at the curb ramp just before you enter the parking lot.

 

[ADAguy]

This is a grey area up for revision to the CBC this code cycle. Construction tolerance is limited to 2% crossslope max and no vertical rise exceeding 1/4"

 

[mtlogcabin]

Why in the world would you put truncated domes in an accessible parking stall access aisle. What is the purpose/reason?

 

[Yikes]

Why in the world would you put truncated domes in an accessible parking stall access aisle. What is the purpose/reason?

Good question. In this instance, the head of the parking stall's striped aisle is the 4th side of a 3-way "T" intersection walkway system. Long story short, this intersection cannot be altered under present circumstances. My concern is that a blind person on the walkway will come to this intersection, and if the intersection is filled with domes, they won't know which of the 3 pathway options is the "hazardous vehicular way".

 

[mark handler]

ADA/CBC 11B-502.4 for accessible parking stall access aisles says: "Changes in level are not permitted. Exception: slopes not steeper than 1:48 shall be permitted."

Questions:

1. Are truncated domes in a detectable warning system per ADA / CBC 11B-705 allowed in the striped access aisle? Or do they constitute a "change in level" that is not allowed? Note that the elevation difference is less than 0.25".

View attachment 7508

2. If a dome that is 0.18" high is NOT allowed, then what are the allowable construction tolerances (surface texture) on an accessible stall and access aisle?

IMHO
No, they can interfere with the loading and unloading of wheelchairs and can be a tripping hazard to those using mobility devices and mobility problems.

 

[steveray]

I can think of a lot of reasons to not have them there, but not one that code would prohibit them from being there...It is not a change and level and they are required on some accessible routes so they are obviously allowed....It does not sound like a raised marked crossing, why are they there at all?