SÃO PAULO, BRAZIL — São Paulo is one of the world's largest megacities. It also has a disturbingly high rate of traffic accident fatalities. With traffic jams that would make even the most hardened Los Angeles resident balk, it's fair to say that the city isn't exactly tailored to pedestrians.

But Avenida Paulista, the city's famed main thoroughfare (it has some of the most expensive real estate in all of Latin America, and is home to frequent protests and parades alike) is getting an overhaul that should give pedestrian advocates hope: Beginning later this fall, São Paulo plans to close the lengthy street to cars every Sunday, letting cyclists, strollers, and rollerbladers roam free.

The city closed Avenida Paulista on Sundays throughout the summer as a pilot project, and found that it didn't disrupt traffic flows. The majority of residents support the closure.

On a recent Sunday, I stumbled upon a closed-down Avenida Paulista. It was filled with people using all kinds of non-car transportation, musicians, and awestruck pedestrians.

There were cyclists all over the place:

Musicians were scattered along the avenue:

And a pair of women walking in front of me were dropping free books on the ground for passersby to take:

Having spent a few harrowing days trying to navigate the city by foot, this was the first time I felt comfortable walking a long distance without fear of getting mowed down by a car. It was a relief.

Avenida Paulista is changing in other ways, too.

In June, Paulista got its first bike lane — a symbol of change in a city that built its first bike lane in 1975, but later turned it into a car tunnel.

Sure, it's just one street in a sprawling metropolis, and plenty of other cities around the world have similar Sunday closures and bike lanes. But these are hopeful developments for a traffic-choked city that puts cars above all other forms of transportation.

More good news: the city's mayor, Fernando Haddad, has also said he plans to significantly expand São Paulo's bike network from 40 miles to 248 miles by 2016.

You have to start somewhere.