Still, with more than 5 million people taking part in blocos last year, by official estimate, the accompanying chaos, litter and traffic nightmares brought by the street parties has sparked a backlash, with some critics calling on City Hall to rein the blocos in.
"While they're a guaranteed good time for some, the street parties bring problems for others," read a recent opinion piece titled "Too Much Joy" in the newspaper Folha de S. Paulo. "The consensus is that many of them have grown too big and need to be held in an appropriate place."
City Hall has brushed off the complaints. This year, officials handed out 15 percent more bloco authorizations than for 2012, giving the green light to 492 street parties.
Speaking at a recent news conference, city Tourism Secretary Antonio Figueira de Mello dismissed criticism as "a conflict of interest between residents."
"With an event that has as big an impact on the city as Carnival, you're always going to have lots of happy people and lots of unhappy people, particularly when events are taking place on the front steps of your building and when they get in the way of your daily routine," Mello said. "Blocos are like street fairs: Everyone likes them, but no one wants one on their street."
Mello stressed that with the rise in the number of blocos comes a ramping up of logistical support.
The number of traffic cops has been increased 25 percent to nearly 1,000 officers in a bid to smooth transportation snarls. Nearly 7,800 municipal guards are to be deployed to encourage revelers to take advantage of this year's 17,200 portable toilets — up from just 900 four years ago. Fines will be levied on those caught urinating in public, Mello said.
Such measures are cold comfort for many residents.
Vinicius Netto, an urbanism professor, said that after "suffering" through the last four Carnivals, he and his girlfriend have decided not to stick around to see if things run more smoothly this time around. They're spending Carnival on an isolated island several hours away.
"Rio is the mecca of Carnival, and I respect that," Netto said. "The problem is that it takes over the city to such an extent that there's no space left for those of us who, for whatever reason, would prefer not to participate."