Mr. Haddad, for his part, is forcefully defending his measures, rejecting claims that they are being imposed without much consultation.

He said in an interview that his mobility proposals were “exhaustively” discussed in his 2012 campaign, and he pointed to statistics published in recent days showing that traffic-related fatalities in São Paulo, including episodes in which pedestrians are hit by cars and killed, fell 18.5 percent to 519 in the first six months of the year from 637 in the same period of 2014.

“How can someone be against the reduction of deaths in the city of São Paulo?” Mr. Haddad asked. Describing São Paulo as a “tense city,” he acknowledged that resistance among some residents to his policies remained entrenched, which he attributed in part to a campaign by some prominent media figures who are seeking to roll back his initiatives.

Mr. Haddad also argued that motorists were benefiting from his policies, in addition to bicyclists, users of public transportation and pedestrians. For instance, traffic is flowing faster in recent weeks along highways where Mr. Haddad lowered the speed limit to 70 kilometers per hour (about 43 miles per hour), after which a 23 percent decline in accidents occurred.

Pondering what to do about dangerous driving has long been a fixture of life in this city.

“The Brazilian chauffeur appears to believe that it is his business, like the matador’s, to reduce to its narrowest the margin between life and death,” the British author Peter Fleming wrote in “Brazilian Adventure,” an irony-soaked 1933 book that unfolded partially in a booming São Paulo.