kathleen anderson added: "i do not understand why they are not subject to the same rules and regs as taxi drivers. they are selling the same service. can someone explain that?" and finally there was this from trustknow1: "i might be old fashioned, but i'll do my own shopping and stick with a traditional taxi service." as always, we welcome your comments at www.pbs.org/newshour, on our facebook page or tweet us at newshour. >> sreenivasan: finally tonight activists with the n.a.a.c.p., has begun an 860-mile journey for justice. the 46-day march began today in selma alabama, goes through five southern states and ends mid-september in washington d.c. the march coincides with next week's 50th anniversary of the signing of the voting right act. the world health organization is asking the international olympic committee to test the water offs rio de janeiro before next august. boating and open water swimming venues contain dangerously high levels of bacteria and viruses accordingings to an analysis conducted by the associated press. the cause? raw sewage. i'm hari sreenivasan. captioning s