A jitney is a institution in the city of Pittsburgh which is essentially a black market cab service. From what I can tell this is a uniquely Pittsburgh phenomena. They are frequently found outside supermarkets in the more urban areas, where they peddle their services to most people who leave the store with a cart. For a small fee they will drive you and your groceries home, they even offer to carry them into your home for an extra fee. Jitneys have been in existence in this city for many decades. Their continued existence is primarily because of two reasons: the lack of grocery stores in minority neighborhoods and the (legal) monopoly over cab service by the yellow cab company. Drivers from yellow cab do not like to service minority areas because of racism and fears of crime. For this reason, jitneys operate call centers and function very much like a legitimate cab service (with significantly cheaper fees). While technically illegal because one needs a license and approval of yellow cab in order to operate a cab service, jitneys have been tolerated by government officials because of the necessity of their services to many people.