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

37.5  Nondiscrimination.

(a) No entity shall discriminate against an individual with a disability in connection with the provision of transportation service.
This section states the general nondiscrimination obligation for entities providing transportation service.  It should be noted that virtually all public and private entities covered by this regulation are also covered by DOJ regulations, which have more detailed statements of general nondiscrimination obligations.
(b) Notwithstanding the provision of any special transportation service to individuals with disabilities, an entity shall not, on the basis of disability, deny to any individual with a disability the opportunity to use the entity's transportation service for the general public, if the individual is capable of using that service.
Under the ADA, an entity may not consign an individual with disabilities to a separate, "segregated," service for such persons, if the individual can in fact use the service for the general public.  This is true even if the individual takes longer, or has more difficulty, than other persons in using the service for the general public.
(c) An entity shall not require an individual with a disability to use designated priority seats, if the individual does not choose to use these seats.
One instance in which this principle applies concerns the use of designated priority seats (e.g., the so-called "elderly and handicapped" seats near the entrances to buses).  A person with a disability (e.g., a visual impairment) may choose to take advantage of this accommodation or not.  If not, it is contrary to the rule for the entity to insist that the individual must sit in the priority seats.
(d) An entity shall not impose special charges, not authorized by this Part, on individuals with disabilities, including individuals who use wheelchairs, for providing services required by this Part or otherwise necessary to accommodate them.
The prohibition on special charges applies to charges for service to individuals with disabilities that are higher than charges for the same or comparable services to other persons.  For example, if a shuttle service charges $20.00 for a ride from a given location to the airport for most people, it could not charge $40.00 because the passenger had a disability or needed to use the shuttle service's lift-equipped van.  Higher mileage charges for using an accessible vehicle would likewise be inconsistent with the rule.  So would charging extra to carry a service animal accompanying an individual with a disability.
If a taxi company charges $1.00 to stow luggage in the trunk, it cannot charge $2.00 to stow a folding wheelchair there.  This provision does not mean, however, that a transportation provider cannot charge nondiscriminatory fees to passengers with disabilities.  The taxi company in the above example can charge a passenger $1.00 to stow a wheelchair in the trunk; it is not required to waive the charge.  This section does not prohibit the fares for paratransit service which transit providers are allowed to charge under §37.131(d).
(e) An entity shall not require that an individual with disabilities be accompanied by an attendant.
A requirement for an attendant is inconsistent with the general nondiscrimination principle that prohibits policies that unnecessarily impose requirements on individuals with disabilities that are not imposed on others.  Consequently, such requirements are prohibited.  An entity is not required to provide attendant services (e.g., assistance in toileting, feeding, dressing) etc.
(f) Private entities that are primarily engaged in the business of transporting people and whose operations affect commerce shall not discriminate against any individual on the basis of disability in the full and equal enjoyment of specified transportation services.  This obligation includes, with respect to the provision of transportation services, compliance with the requirements of the rules of the Department of Justice concerning eligibility criteria, making reasonable modifications, providing auxiliary aids and services, and removing barriers (28 CFR 36.301 -- 36.306).

(g)  An entity shall not refuse to serve an individual with a disability or require anything contrary to this Part because its insurance company conditions coverage or rates on the absence of individuals with disabilities or requirements contrary to this Part.
This section also prohibits denials of service or the placing on services of conditions inconsistent with this Part on individuals with disabilities because of insurance company policies or requirements.  If an insurance company told a transit provider that it would withdraw coverage, or raise rates, unless a transit provider refused to carry persons with disabilities, or unless the provider refused to carry three-wheeled scooters, this would not excuse the provider from providing the service as mandate by this Part.  This is not a regulatory requirement on insurance companies, but simply says that covered entities must comply with this Part, even in the face of difficulties with their insurance companies.
(h) It is not discrimination under this Part for an entity to refuse to provide service to an individual with disabilities because that individual engages in violent, seriously disruptive, or illegal conduct.  However, an entity shall not refuse to provide service to an individual with disabilities solely because the individual's disability results in appearance or involuntary behavior that may offend, annoy, or inconvenience employees of the entity or other persons.
This provision must also be considered in light of the fact that an entity may refuse service to someone who engages in violent, seriously disrputive, or illegal conduct.  If an entity may legitimately refuse service to someone, it may condition service to him on actions that would mitigate the problem.  The entity could require an attendant as a condition of providing service it otherwise had the right to refuse.
The rule also points out that involuntary conduct related to a disability that may offend or annoy other persons, but which does not pose a direct threat, is not a basis for refusal of transportation.  For example, some persons with Tourette's syndrome may make involuntary profane exclamations.  These may be very annoying or offensive to others, but would not be a ground for denial of service.  Nor would it be consistent with the nondiscrimination requirements of this Part to deny service based on fear or misinformation about the a disability.  For example, a transit provider could not deny service to a person with HIV disease because its personnel or other passengers are afraid of being near people with that condition.