49 CFR §37.129

1. (a)Except as provided in this section, complementary paratransit service for ADA paratransit eligible persons shall be origin-to-destination service.
2. (b)Complementary paratransit service for ADA paratransit eligible persons described in § 37.123(e)(2) of this part may also be provided by on-call bus service or paratransit feeder service to an accessible fixed route, where such service enables the individual to use the fixed route bus system for his or her trip.
3. (c)Complementary paratransit service for ADA eligible persons described in § 37.123(e)(3) of this part also may be provided by paratransit feeder service to and/or from an accessible fixed route.