The latest demonstrations have crystallized around resistance to new fare increases, making it the latest in a sequence of campaigns of dissent over public transportation dating to the Vintém Revolt of 1879, when protesters in Rio de Janeiro challenged Brazil’s monarchy over fares for trolley cars. “The hike in bus fares were the spark for this to happen,” said Maurício Santoro, an adviser here to Amnesty International. “Public transportation in Brazil is expensive, unsafe and poorly managed, especially impacting poor commuters who have no choice but to rely on these systems.”