However the dimension only applies to handrails at a ramp or stair. At restroom grab bars, Section 609.3 Grab Bar Spacing of the 2010 Standards (p. 293 of the ADA Companion Guide) states that the space between the wall and grab bar shall be 1 �" (no range allowed).  Thus, it is 1 1/2" only.

At ramps, a 12" horizontal extension of handrails at top and bottom is required if the handrails are not continuous. This extension should be horizontal and parallel to the path of travel.

However, at a stair, a 12" extension at the bottom of the stair is required, but not horizontally.  The extension on the top of the stair has to extend horizontally and parallel with the path of travel.

An accessible route must be 36" wide minimum.  Door widths must be 32" min.

Therefore, doorways along the accessible route can reduce the accessible route width to 32" min.  A doorway can be a cased opening along the route, and the width can be decreased to 32" for a length of 24".

In the 2010 Standards, it is more clear that a door swing can overlap the turning space in a room.

304.4 Door Swing. Door shall be permitted to swing into turning spaces

By the same token, door swings cannot overlap clear floor space of any fixtures or dressing rooms. 

603.2.3 Door Swing. Doors shall not swing into the clear floor space or clearance required for any fixture. Doors shall be permitted to swing into the required turning space.

This is true because if a person is using a fixture like a lavatory for example, and a door swings into the clear floor space while they are using it, they will get hit. 

There is an exception that in a single user restroom or dressing room, the door can swing in if there is a 30"x48" space beyond the swing of the door.

In restrooms, a 60"x 56" clear floor space is required at water closets.  But if you think about it, the floor space is not exactly "clear" because there is a toilet in the way. 

So the 2010 Standards understood that , allows an overlap of the clear floor space with the water closet, shelving, toilet paper dispensers, grab bars and other elements that are needed in the restroom.