Excerpted from the "ADA Title III Regulation 28 CFR Part 36" http://www.ada.gov/reg3a.html
Sec.36.304 Removal of barriers.
(a) General. A public accommodation shall remove architectural barriers in existing facilities, including communication barriers that are structural in nature, where such removal is readily achievable, i.e., easily accomplishable and able to be carried out without much difficulty or expense.
(b) Examples. Examples of steps to remove barriers include, but are not limited to, the following actions --
(1) Installing ramps;
(2) Making curb cuts in sidewalks and entrances;
(3) Repositioning shelves;
(4) Rearranging tables, chairs, vending machines, display racks, and other furniture;
(5) Repositioning telephones;
(6) Adding raised markings on elevator control buttons;
(7) Installing flashing alarm lights;
(8) Widening doors;
(9) Installing offset hinges to widen doorways;
(10) Eliminating a turnstile or providing an alternative accessible path;
(11) Installing accessible door hardware;
(12) Installing grab bars in toilet stalls;
(13) Rearranging toilet partitions to increase maneuvering space;
(14) Insulating lavatory pipes under sinks to prevent burns;
(15) Installing a raised toilet seat;
(16) Installing a full-length bathroom mirror;
(17) Repositioning the paper towel dispenser in a bathroom;
(18) Creating designated accessible parking spaces;
(19) Installing an accessible paper cup dispenser at an existing inaccessible water fountain;
(20) Removing high pile, low density carpeting; or
(21) Installing vehicle hand controls.
(c) Priorities. A public accommodation is urged to take measures to comply with the barrier removal requirements of this section in accordance with the following order of priorities.
(1) First, a public accommodation should take measures to provide access to a place of public accommodation from public sidewalks, parking, or public transportation. These measures include, for example, installing an entrance ramp, widening entrances, and providing accessible parking spaces.
(2) Second, a public accommodation should take measures to provide access to those areas of a place of public accommodation where goods and services are made available to the public. These measures include, for example, adjusting the layout of display racks, rearranging tables, providing Brailled and raised character signage, widening doors, providing visual alarms, and installing ramps.
(3) Third, a public accommodation should take measures to provide access to restroom facilities. These measures include, for example, removal of obstructing furniture or vending machines, widening of doors, installation of ramps, providing accessible signage, widening of toilet stalls, and installation of grab bars.
(4) Fourth, a public accommodation should take any other measures necessary to provide access to the goods, services, facilities, privileges, advantages, or accommodations of a place of public accommodation.
(d) Relationship to alterations requirements of subpart D of this part.
(1) Except as provided in paragraph (d)(2) of this section, measures taken to comply with the barrier removal requirements of this section shall comply with the applicable requirements for alterations in Sec.36.402 and Sec..36.404 -36.406 of this part for the element being altered. The path of travel requirements of Sec.36.403 shall not apply to measures taken solely to comply with the barrier removal requirements of this section.
(2) If, as a result of compliance with the alterations requirements specified in paragraph (d)(1) of this section, the measures required to remove a barrier would not be readily achievable, a public accommodation may take other readily achievable measures to remove the barrier that do not fully comply with the specified requirements. Such measures include, for example, providing a ramp with a steeper slope or widening a doorway to a narrower width than that mandated by the alterations requirements. No measure shall be taken, however, that poses a significant risk to the health or safety of individuals with disabilities or others.
(e) Portable ramps. Portable ramps should be used to comply with this section only when installation of a permanent ramp is not readily achievable. In order to avoid any significant risk to the health or safety of individuals with disabilities or others in using portable ramps, due consideration shall be given to safety features such as nonslip surfaces, railings, anchoring, and strength of materials.
(f) Selling or serving space. The rearrangement of temporary or movable structures, such as furniture, equipment, and display racks is not readily achievable to the extent that it results in a significant loss of selling or serving space.
(g) Limitation on barrier removal obligations.
(1) The requirements for barrier removal under Sec.36.304 shall not be interpreted to exceed the standards for alterations in subpart D of this part.
(2) To the extent that relevant standards for alterations are not provided in subpart D of this part, then the requirements of Sec.36.304 shall not be interpreted to exceed the standards for new construction in subpart D of this part.
(3) This section does not apply to rolling stock and other conveyances to the extent that Sec.36.310 applies to rolling stock and other conveyances.