This section contains amendments from May 21, 1996.

Material shown in italics is from the preamble of the of the regulation and is presented for clarification only.

37.3  Definitions

As used in this Part:

"Accessible" means, with respect to vehicles and facilities, complying with the accessibility requirements of Parts 37 and 38 of this title.

"Administrator" means Administrator of the Urban Mass Transportation Administration, or his or her designee.

"Alteration" means a change to an existing facility, including, but not limited to, remodeling, renovation, rehabilitation, reconstruction, historic restoration, changes or rearrangement in structural parts or elements, and changes or rearrangement in the plan configuration of walls and full-height partitions.  Normal maintenance, reroofing, painting or wallpapering, asbestos removal, or changes to mechanical or electrical systems are not alterations unless they affect the usability of the building or facility.

"The Act" or "ADA" means the Americans with Disabilities Act of 1990 (Pub. L. 101-336, 104 Stat. 327, 42 U.S.C. 12101-12213 and 47 U.S.C. 225 and 611), as it may be amended from time to time.

"Automated guideway transit system" or "AGT" means a fixed-guideway transit system which operates with automated (driverless) individual vehicles or multi-car trains.  Service may be on a fixed schedule or in response to a passenger-activated call button.

"Auxiliary aids and services" includes:
  1. Qualified interpreters, notetakers, transcription services, written materials, telephone headset amplifiers, assistive listening devices, assistive listening systems, telephones compatible with hearing aids, closed caption decoders, closed and open captioning, text telephones (also known as telephone devices for the deaf, or TDDs), videotext displays, or other effective methods of making aurally delivered materials available to individuals with hearing impairments;
  2. Qualified readers, taped texts, audio recordings, Brailled materials, large print materials, or other effective methods of making visually delivered materials available to individuals with visual impairments;
  3. Acquisition or modification of equipment or devices; or
  4. Other similar services or actions.
"Bus" means any of several types of self-propelled vehicles, generally rubber-tired, intended for use on city streets, highways, and busways, including but not limited to minibuses, forty- and thirty-foot buses, articulated buses, double-deck buses, and electrically powered trolley buses, used by public entities to provide designated public transportation service and by private entities to provide transportation service including, but not limited to, specified public transportation services.  Self-propelled, rubber-tired vehicles designed to look like antique or vintage trolleys are considered buses. "Commerce" means travel, trade, transportation, or  communication among the several states, between any foreign country or any territory or possession and any state, or between points in the same state but through another state or foreign country.

"Commuter authority" means any state, local, regional authority, corporation, or other entity established for purposes of providing commuter rail transportation (including, but not necessarily limited to, the New York Metropolitan Transportation Authority, the Connecticut Department of Transportation, the Maryland Department of Transportation, the Southeastern Pennsylvania Transportation Authority, the New Jersey Transit Corporation, the Massachusetts Bay Transportation Authority, the Port Authority Trans-Hudson Corporation, and any successor agencies) and any entity created by one or more such agencies for the purposes of operating, or contracting for the operation of, commuter rail transportation.
The definition of "commuter authority" includes a list of commuter rail operators drawn from a statutory reference in the ADA.  It should be noted that this list is not exhaustive.  Other commuter rail operators (e.g., in Chicago or San Francisco) would also be encompassed by this definition.
"Commuter bus service" means fixed route bus service, characterized by service predominantly in one direction during peak periods, limited stops, use of multi-ride tickets, and routes of extended length, usually between the central business district and outlying suburbs.  Commuter bus service may also include other service, characterized by a limited route structure, limited stops, and a coordinated relationship to another mode of transportation.
We received several comments on the definition of "commuter bus service."  This term is important because the ADA does not require public entities to provide complementary paratransit with respect to commuter bus service.  One of these comments suggested the definition be clarified so as not to exclude a service that provides some service opposite to the main rush hour traffic flow.  The existing definition, which talks of service "predominantly," rather than exclusively, in one direction, does not exclude such service.

Another comment suggested that the term specifically include dedicated bus service to commuter rail routes.  It is reasonable to infer that commuter bus service was excepted from the ADA's paratransit requirement because of the differences between the characteristics of commuter service and regular mass transit service.  Typically, commuter bus service does not attempt to cover an area comprehensively, but rather has a limited route structure connecting a limited number of origins and destinations. Typically, this service is intended to interface with another mode of transportation (e.g., the automobile, with the connection occurring at a park-and-ride facility).  Trips are often primarily for limited purposes (e.g., work trips).

We construe the commuter bus category to apply to a range of services which differ significantly from the model of urban mass transportation fixed route service to which Congress attached the complementary paratransit obligation. For this range of services, because of their differences from urbam mass transportation fixed route service, paratransit is not a necessary or appropriate complement.

A number of services other than work-trip oriented commuter service are within this range.   The commenter's dedicated service to commuter rail, some airport shuttle services, public university shuttles, or intercity rail connecter services all have limited routes and limited origins and destinations, do not attempt to provide areawide transportation service, interface with one or more transportation modes, and have limited purposes.   For this reason, we have included systems with these characteristics in the definition of "commuter bus service."  The implications of this change for certain specific systems are discussed in the discussion of Subpart B in the preamble to this document.

The definition of "commuter bus service" is important because the ADA does not require complementary paratransit to be provided with respect to commuter bus service operated by public entities.  The rationale that may be inferred for the statutory exemption for this kind of service concerns its typical characteristics (e.g., no attempt to comprehensively cover a service area, limited route structure, limited origins and destinations, interface with another mode of transportation, limited purposes of travel).  These characteristics can be found in some transportation systems other than bus systems oriented toward work trips.  For example, bus service that is used as a dedicated connecter to commuter or intercity rail service, certain airport shuttles, and university bus systems share many or all of these characteristics.  As explained further in the discussion of Subpart B, the Department has determined that it is appropriate to cover these services with the requirements applicable to commuter bus systems.
"Commuter rail transportation" means short-haul rail passenger service operating in metropolitan and suburban areas, whether within or across the geographical boundaries of a state, usually characterized by reduced fare, multiple ride, and commutation tickets and by morning and evening peak period  operations.  This term does not include light or rapid rail transportation.

"Commuter rail car" means a rail passenger car obtained by a commuter authority for use in commuter rail transportation.

"Demand responsive system" means any system of transporting individuals, including the provision of designated public transportation service by public entities and the provision of transportation service by private entities, including but not limited to specified public transportation service, which is not a fixed route system.

"Designated public transportation" means transportation provided by a public entity (other than public school transportation) by bus, rail, or other conveyance (other than transportation by aircraft or intercity or commuter rail transportation) that provides the general public with general or special service, including charter service, on a regular and continuing basis.
The definitions of "designated public transportation" and "specified public transportation" exclude transportation by aircraft.  Persons interested in matters concerning access to air travel for individuals with disabilities should refer to 14 CFR Part 382, the Department's regulation implementing the Air Carrier Access Act.  
"Disability" means, with respect to an individual, a physical or mental impairment that substantially limits one or more of the major life activities of such individual; a record of such an impairment; or being regarded as having such an impairment.
  1. The phrase "physical or mental impairment" means -
  2. (i) Any physiological disorder or condition, cosmetic disfigurement, or anatomical loss affecting one or more of the following body systems: neurological, musculoskeletal, special sense organs, respiratory including  speech organs, cardiovascular, reproductive, digestive, genito-urinary, hemic and lymphatic, skin, and endocrine;
    (ii) Any mental or psychological disorder, such as mental retardation, organic brain syndrome, emotional or mental illness, and specific learning disabilities.
    (iii) The term "physical or mental impairment" includes, but is not limited to, such contagious or noncontagious diseases and conditions as orthopedic, visual, speech, and hearing impairments; cerebral palsy, epilepsy, muscular dystrophy, multiple sclerosis, cancer, heart disease, diabetes, mental retardation, emotional illness, specific learning disabilities, HIV disease, tuberculosis, drug addiction and alcoholism.
    (iv) The phrase "physical or mental impairment" does not include homosexuality or bisexuality.
  3. The phrase "major life activities" means functions such as caring for one's self, performing manual tasks, walking, seeing, hearing, speaking, breathing, learning, and working; or
  4. The phrase "has a record of such an impairment"  means has a history of, or has been misclassified as having,  a mental or physical impairment that substantially limits one or more major life activities; or
  5. The phrase "is regarded as having such an impairment" means --
  6. (i) Has a physical or mental impairment that does not substantially limit major life activities, but which is treated by a public or private entity as constituting such a limitation;    
    (ii) Has a physical or mental impairment that substantially limits a major life activity only as a result of the attitudes of others toward such an impairment; or
    (iii) Has none of the impairments defined in paragraph (1) of this definition but is treated by a public or private entity as having such an impairment.
  7. The term "disability" does not include --
(i) Transvestism, transsexualism, pedophilia, exhibitionism, voyeurism, gender identity disorders not resulting from physical impairments, or other sexual behavior disorders;
(ii) Compulsive gambling, kleptomania, or pyromania;
(iii) Psychoactive substance abuse disorders resulting from the current illegal use of drugs.
A few comments addressed "disability."  Some suggested removing "permanent or temporary," suggesting that this language is unnecessary.  The DOJ definition does not include these words, so we have deleted them for consistency.  In our view, the terms are unnecessary because any condition that meets the criteria of the definition,  regardless of its duration, is a disability.  Other comments suggested adding specific mention of such conditions as cognitive or energy deficient disorders and environmental illness. The DOJ definition does not cite these conditions specifically.  The list of conditions in the definition, in any case, is not exhaustive, and does not exclude unspecified conditions that meet its criteria.  For these reasons, we did not add mention of the conditions.
One commenter suggested a much more detailed definition of "mental disability."  DOJ did not adopt this comment, which was also made to its proposed rules, and we think it best to remain consistent with DOJ.  Moreover, the details of the definition of disability are probably somewhat less important in the DOT rule than in the DOJ or Equal Employment Opportunity Commission (EEOC) rules, since it is functional ability to use fixed route transit, rather than precise diagnosis or classification of a disability, which is most relevant to the provision of transportation under this rule.
"Facility" means all or any portion of buildings, structures, sites, complexes, equipment, roads, walks, passageways, parking lots, or other real or personal property, including the site where the building, property, structure, or equipment is located.
In the definition of "facility," the Department has deleted the reference in DOJ's definition to "rolling stock and other conveyances."   In the DOT rule, there is a clear demarcation between facilities and vehicles, and we believe that the definition will be clearer for the deletion of these terms.
Since the facility requirements of this Part refer to facilities involved in the provision of designated or specified public transportation, airport facilities are not covered by this Part.  DOJ makes clear that public and private airport facilities are covered under its Title II and Title III regulations, respectively.  The examples given in the definition of "facility" all relate to ground transportation.  We would point out that, since transportation by passenger vessels is covered by this rule and by DOJ rules, such vessel-related facilities as docks, wharfs, vessel terminals etc. fall under this definition.  It is intended that specific requirements for vessels and related facilities will be set forth in future rulemaking.
"Fixed route system" means a system of transporting individuals (other than by aircraft), including the provision of designated public transportation service by public entities and the provision of transportation service by private entities, including, but not limited to, specified public transportation service, on which a vehicle is operated along a prescribed route according to a fixed schedule.
The most frequent subjects of comment were the definitions of "fixed route" and "demand responsive"  service.  The most frequent comment was that the definitions strayed too far from the ADA statutory definitions of the terms.  Commenters objected to references to the presence or absence of an advance request for service as a distinguishing point between the two kinds of service. They also objected to the definition's statement that the terms applied to transportation "including but not limited to" designated and specified transportation services. While an advance request for service is a key characteristic distinguishing  fixed route and demand responsive service, this characteristic is not included in the statutory text, and so we will delete it from the regulatory text.
The reason for the "including but not limited to" language has to do with the structure of Title III of the ADA.  Private entities not primarily engaged in the business of transporting people do not, by statutory definition, provide specified public transportation service.  The definitions of fixed route and demand responsive transportation must apply to these entities as well as public entities and private entities who are primarily engaged in the business of transporting people.  For clarity, the language has been reorganized to make it clear that it applies only to private entities.

The definitions of "fixed route system" and "demand responsive system" derive directly from the ADA's definitions of these terms.Some systems, like a typical city bus system or a dial-a-ride van system, fit clearly into one category or the other.  Other systems may not so clearly fall into one of the categories.  Nevertheless, because how a system is categorized has consequences for the requirements it must meet, entities must determine, on a case-by-case base, into which category their systems fall.

In making this determination, one of the key factors to be considered is whether the individual, in order to use the service, must request the service, typically by making a call.

With fixed route service, no action by the individual is needed to initiate public transportation.  If an individual is at  a bus stop at the time the bus is scheduled to appear, then that individual will be able to access the transportation system.

With demand-responsive service, an additional step must be taken by the individual before he or she can ride the bus, i.e., the individual must make a telephone call.(S. Rept. 101-116 at 54).

Other factors, such as the presence or absence of published schedules, or the variation of vehicle intervals in anticipation of differences in usage, are less important in making the distinction between the two types of service.  If a service is provided along a given route, and a vehicle will arrive at certain times regardless of whether a passenger actively requests the vehicle, the service in most cases should be regarded as fixed route rather than demand responsive.

At the same time, the fact that there is an interaction between a passenger and transportation service does not necessarily make the service demand responsive.  For many types of service (e.g., intercity bus, intercity rail) which are clearly fixed route, a passenger has to interact with an agent to buy a ticket.   Some services (e.g., certain commuter bus or commuter rail operations) may use flag stops, in which a vehicle along the route does not stop unless a passenger flags the vehicle down.  A traveler staying at a hotel usually makes a room reservation before hopping on the hotel shuttle.  This kind of interaction does not make an otherwise fixed route service demand responsive.

On the other hand, we would regard a system that permits user-initiated deviations from routes or schedules as demand-responsive..  For example, if a rural public transit system (e.g., a section 18 recipient) has a few fixed routes, the fixed route portion of its system would be subject to the requirements of Subpart F for complementary paratransit service.   If the entity changed its system so that it operated as a route-deviation system, we would regard it as a demand responsive system.  Such a system would not be subject to complementary paratransit requirements.
"High speed rail" means a rail service having the characteristics of intercity rail service which operates primarily on a dedicated guideway or track not used, for the most part, by freight, including, but not limited to, trains on welded rail, magnetically levitated (maglev) vehicles on a special guideway, or other advanced technology vehicles, designed to travel at speeds in excess of those possible on other types of railroads.

"Individual with a disability" means a person who has a disability, but does not include an individual who is currently engaging in the illegal use of drugs, when a public or private entity acts on the basis of such use.
The definition of "individual with a disability" excludes someone who is currently engaging in the illegal use of drugs, when a covered entity is acting on the basis of such use.  This concept is more important in employment and public accommodations contexts than it is in transportation, and is discussed at greater length in the DOJ and EEOC rules.  Essentially, the definition says that, although drug addiction (i.e., the status or a diagnosis of being a drug abuser) is a disability, no one is regarded as being an individual with a disability on the basis of current illegal drug use.

Moreover, even if an individual has a disability, a covered entity can take action against the individual if that individual is currently engaging in illegal drug use.  For example, if a person with a mobility or vision impairment is ADA paratransit eligible, but is caught possessing or using cocaine or marijuana on a paratransit vehicle, the transit provider can deny the individual further eligibility.  If the individual has successfully undergone rehabilitation or is no longer using drugs, as explained in the preamble to the DOJ rules, the transit provider could not continue to deny eligibility on the basis that the individual was a former drug user or still was diagnosed as a person with a substance abuse problem.
"Intercity rail passenger car" means a rail car, intended for use by revenue passengers, obtained by Amtrak for use in intercity rail transportation.
The Department received a few comments suggesting amendment of the definition of "intercity passenger rail car" to encompass rail cars on systems run by entities other than Amtrak.  This issue is addressed in the Applicability subpart.  Another commenter wanted this definition to  specify that it applied only to rail passenger cars with accommodations intended for revenue passengers.  We recognize that passenger railroads have cars that are not intended to accommodate passengers (e.g., baggage cars, dormitory cars for workers)).  While we do not think that these cars could easily be confused with rail passenger cars, there is no harm in adding the requested language (which the Access Board also has done).
"Intercity rail transportation" means transportation provided by the National Railroad Passenger Corporation (Amtrak).

"Light rail" means a streetcar-type vehicle operated on city streets, semi-exclusive rights of way, or exclusive rights of way.  Service may be provided by step-entry vehicles or by level boarding.

"New vehicle" means a vehicle which is offered for sale or lease after manufacture without any prior use.

"Operates" includes, with respect to a fixed route or demand responsive system, the provision of transportation service by a public or private entity itself or by a person under a contractual or other arrangement or relationship with the entity.
We have added a reference to private entities in the definition of "operates."  This is an important definition, which forms the basis for the "stand in the shoes" provision affecting contractors to other transportation providers. Comments suggested that it was reasonable to apply the "stand in the shoes" concept to private contractors to private entities, as well as private contractors to public entities.  We agree, and this addition is consistent with this determination.
"Over-the-road bus" means a bus characterized by an elevated passenger deck located over a baggage compartment.
The ADA's definition of "over-the-road bus" may also be somewhat narrower than the common understanding of the term.  The ADA definition focuses on a bus with an elevated passenger deck over a baggage compartment (i.e., a "Greyhound-type" bus).  Other types of buses commonly referred to as "over-the-road buses," which are sometimes used for commuter bus or other service, do not come within this definition.  Only buses that do come within the definition are subject to the over-the-road bus exception to accessibility requirements in Title III of the ADA.
"Paratransit" means comparable transportation service required by the ADA for individuals with disabilities who are unable to use fixed route transportation systems.
We defined "paratransit" in order to note its specialized usage in the rule.  Part 37 uses this term to refer to the complementary paratransit service comparable to public fixed route systems which must be provided.  Typically, paratransit is provided in a demand responsive mode.  Obviously, the rule refers to a wide variety of demand responsive services that are not "paratransit," in this specialized sense.
"Private entity" means any entity other than a public entity.

"Public entity" means:
(a) Any state or local government;
(b) Any department, agency, special purpose district, or other instrumentality of one or more state or local governments; and
(c) The National Railroad Passenger Corporation (Amtrak) and any commuter authority.
"Purchase or lease," with respect to vehicles, means the time at which an entity is legally obligated to obtain the vehicles, such as the time of contract execution.

"Public school transportation" means transportation by schoolbus vehicles of schoolchildren, personnel, and equipment to and from a public elementary or secondary school and school-related activities.

"Rapid rail" means a subway-type transit vehicle railway operated on exclusive private rights of way with high level platform stations.  Rapid rail also may operate on elevated or at grade level track separated from other traffic.

"Remanufactured vehicle" means a vehicle which has been structurally restored and has had new or rebuilt major components installed to extend its service life.

"Secretary" means the Secretary of Transportation or his/her designee.

"Section 504" means section 504 of the Rehabilitation Act of 1973 (Pub. L. 93-112, 87 Stat. 394, 29 U.S.C. 794), as amended.

"Service animal" means any guide dog, signal dog, or other animal individually trained to work or perform tasks for an individual with a disability, including, but not limited to, guiding individuals with impaired vision, alerting individuals with impaired hearing to intruders or sounds, providing minimal protection or rescue work, pulling a wheelchair, or fetching dropped items.

"Solicitation" means the closing date for the submission of bids or offers in a procurement.

"Specified public transportation" means transportation by bus, rail, or any other conveyance (other than aircraft) provided by a private entity to the general public, with general or special service (including charter service) on a regular and continuing basis.

"Station" means, with respect to intercity and commuter rail transportation, the portion of a property located appurtenant to a right of way on which intercity or commuter rail transportation is operated, where such portion is used by the general public and is related to the provision of such transportation, including passenger platforms, designated waiting areas, restrooms, and, where a public entity providing rail transportation owns the property, concession areas, to the extent that such public entity exercises control over the selection, design, construction, or alteration of the property, but this term does not include flag stops (i.e., stations which are not regularly scheduled stops but at which trains will stop board or detrain passengers only on signal or advance notice).
The Department received a few comments comments on the definition of "station."  Two asked for the addition of a definition of "flag stop," a term used in the NPRM definition of "station."  We have added a definition of this term, derived from the Department's 1979 section 504 rule, as a parenthetical in the "station" definition.  Other comments noted that the definition applies to intercity and commuter but not to light and rapid rail systems.  The "station" definition in the ADA itself shares this limitation.  The addition of definitions of "light rail" and "rapid rail" should help to provide clarity in this area.
"Transit facility" means, for purposes of determining the number of text telephones needed consistent with 10.3.1(12) of Appendix A to this Part, a physical structure the primary function of which is to facilitate access to and from a transportation system which has scheduled stops at the structure.  The term does not include an open structure or a physical structure the primary purpose of which is other than providing transportation services.
The Department has added a new definition of "transit facility."  This definition relates only to the Access Board guideline requirement for TDDs, which applies to transit facilities.  Only closed structures the primary function of which serves as a transit facility are made subject to the TDD requirement.  The aim of the definition is to avoid a potentially burdensome mandate for TDDs in structures not primarily used for transportation purposes.  Consistent with Access Board terminology, the term "text telephone" is used interchangably in the rule with "TDD."
The definition of "transit facility" applies only with reference to the TDD requirement of Appendix A to this Part.  The point of the definition is to exempt from TDD requirements open structures, like bus shelters, or facilities which are not used primarily as transportation stops or terminals.  For example, a drug store in a small town may sell intercity bus tickets, and people waiting for the bus may even wait for the bus inside the store.  But the drug store's raison d'etre is not to be a bus station.  Its transportation function is only incidental.   Consequently, its obligations with respect to TDDs would be those required of a place of public accommodation by DOJ rules.
"UMT Act" means the Urban Mass Transportation Act of 1964, as amended (49 U.S.C. App. 1601 et seq.).

"Used vehicle" means a vehicle with prior use.
In the definition of "used vehicle," we have deleted a reference to June 1990 as a trigger date for a vehicle being considered as used.  This date, which derived from the ADA's legislative history, had relevance with the vehicle accessibility requirements first went into effect in August 1990.  Now, however, any vehicle with prior use is considered to be "used."

A "used vehicle" means a vehicle which has prior use; prior, that is, to its acquisition by its present owner or lessee.  The definition is not relevant to existing vehicles in one's own fleet, which were obtained before the ADA vehicle accessibility requirements took effect.
"Vanpool" means a voluntary commuter ridesharing arrangement, using vans with a seating capacity greater than 7 persons (including the driver) or buses, which provides transportation to a group of individuals traveling directly from their homes to their regular places of work within the same geographical area, and in which the commuter/driver does not receive compensation beyond reimbursement for his or her costs of providing the service.
In response to comments concerning the coverage of vanpools under the rule, we have added a definition of "vanpool."  This term refers to ridesharing arrangements for work trips in which the driver is, essentially, a volunteer.  The coverage of vanpools is discussed in the Applicability subpart.

A "vanpool" is a voluntary commuter ridesharing arrangement using a van with a seating capacity of more than seven persons, including the driver..  Carpools are not included in the definition.  There are some systems using larger vehicles (e.g., buses) that operate, in effect, as vanpools.  This definition encompasses such systems.  Vanpools are used for daily work trips, between commuters' homes (or collection points near them) and work sites (or drop points near them).  Drivers are themselves commuters who are either volunteers who receive no compensation for their efforts or persons who are reimbursed by other riders for the vehicle, operating, and driving costs.
"Vehicle", as the term is applied to private entities, does not include a rail passenger car, railroad locomotive, railroad freight car, or railroad caboose, or other rail rolling stock described in section 242 or Title III of the Act.

"Wheelchair" means a mobility aid belonging to any class of three or four-wheeled devices, usable indoors, designed for and used by individuals with mobility impairments, whether operated manually or powered.  A "common wheelchair" is such a device which does not exceed 30 inches in width and 48 inches in length measured two inches above the ground, and does not weigh more than 600 pounds when occupied.
Several comments addressed the definition of "wheelchair."  Some suggested it be expanded (e.g., to include canes and walkers), others that it be clarified or contracted (e.g., with respect to three-wheeled scooters and electric wheelchairs).  Most commenters supported the  definition's inclusion of "non-traditional" mobility devices.  One comment suggested the substitution of the term "mobility device" for "wheelchair, which we are not doing since "wheelchair" is used in the statute.  We have incorporated into the definition the Access Board's definition of the related term "common wheelchair" (i.e., a wheelchair that fits on a 30" x 48" lift platform and does not weigh more than 600 pounds when occupied).

The definition of "wheelchair" includes a wide variety of mobility devices.  This inclusiveness is consistent with the legislative history of the ADA (See S. Rept. 101-116 at 48).  While some mobility devices may not look like many persons' traditional idea of a wheelchair, three and four wheeled devices, of many varied designs, are used by individuals with disabilities and must be transported.

The definition of "common wheelchair," developed by the Access Board, is intended to help transit providers determine which wheelchairs they have to carry.  The definition involves an "envelope" relating to the Access Board requirements for vehicle lifts.

A lift conforming to Access Board requirements is 30" x 48" and capable of lifting a wheelchair/occupant combination of up to 600 pounds.  Consequently, a common wheelchair is one that fits these size and weight dimensions.  Devices used by individuals with disabilities that do not fit this envelope (e.g., many "gurneys") do not have to be carried.