legal or site constraints; and shall be connected to streets, sidewalks, or pedestrian paths by an accessible route complying with 4.3 and 4.4. The slope of the pad parallel to the roadway shall, to the extent practicable, be the same as the roadway. For water drainage, a maximum slope of 1:50 (2%) perpendicular to the roadway is allowed. (2) Where provided, new or replaced bus shelters shall be installed or positioned so as to permit a wheelchair or mobility aid user to enter from the public way and to reach a location having a minimum clear floor area of 30 inches by 48 inches entirely within the perimeter of the shelter. Such shelters shall be connected by an accessible route to the boarding area provided under paragraph (1) of this section. (3) Where provided, all new bus route identification signs shall comply with 4.30.5. In addition, to the maximum extent practicable, all new bus route identification signs shall comply with 4.30.2 and 4.30.3...

The City of San Francisco has policies covering construction barricades, scaffolding, sidewalk tables and chairs, and sub-sidewalk basements that include requirements for pedestrians with vision impairments.

ADAAG 4.1.1(4) Temporary Structures.
These guidelines cover temporary buildings and facilities as well as permanent facilities [...] Examples of temporary buildings or facilities covered by these guidelines include, but are not limited to: reviewing stands [...], bleacher areas, exhibit areas [...], or temporary safe pedestrian passage around a construction site.