The clean streets is noticeable for those who comes to Curitiba. The habit of not throwing garbage on the floor gets to be contagious.
It is quite common to see people walking with something to be thrown in the trash until finding a public trash can. I remember a TV campaign in which Oscar Schmidt (former basketball player) was sitting on a park bench in Curitiba and beside him, a man reading a newspaper. From the banch, Oscar began to observe people doing amazing shots of their waste, as in basketball, in the dumps. After much notice, he throws his empty glass of soda toward a trash can. The pitch gives the rim and falls out of trash can. At this point, the man stops reading the newspaper, looks at him and says, "You are not from here, are you?".
One explanation for the success of cleaning the streets of Curitiba is that the cleaner the city is, the more people care. Curitiba recently received the title of The Cleanest City among other major cities in Brazil surveyed by Globo Network. The test consists of not to do the cleaning in the busiest part of town for 24 hours and then collected all the garbage to be cumbersome. Curitiba has collected only 33 kg against 203 kg of Goiania, 540 kg of São Paulo, 680 kg of Rio de Janeiro, 710 kg of Belém, a ton of Fortaleza and 1.2 tons of Salvador.
And this civility to keep the city clean is one of the 50 Reasons to Love Curitiba listed by Gazeta do Povo.