If you stay at the Sheraton you'll either have to use their car service, which is very expensive, or taxis, which are cheap and easy to get. Everywhere except at the Sheraton, that is. Taxis are not allowed to wait inside the Sheraton compound. A bell person will go out to the main road and try to get one for you if you insist. But empty taxis do not often travel that road, as it is not used by very many people. The situation is similar to that at the Santiago Sheraton, except that the Santiago hotel is in a safe neighborhood and taxis can wait at the bottom of the hill. Although I generally love Starwood, I never put any visitors in the Sheraton Rio.