"Paratransit System:" Paratransit systems are those which operate alongside public transportation systems to provide special amenities for the physically- and visually-impaired. These services may also be provided by private companies or nonprofit organizations.
"Vision-impaired:" The ADA defines disability as "a physical or mental impairment that substantially limits one or more of the major life activities of such individual." Vision impairment falls under this definition. Generally, for a person to take advantage of alternative transportation services, certification of such impairment by a doctor is required. A pass or identification card is typically issued, which must be presented when boarding.