New York City is right in the middle of its Summer Streets program (there's a video above) -- in which the city is closing main a main thoroughfare to automobile traffic for three Saturday mornings in August. The streets are left to pedestrians and bicyclists -- residents can bike from the Brooklyn Bridge to the middle of Central Park without encountering a car.

According to the New York Times , "having a major thoroughfare through Manhattan free of cars created a giddy sort of excitement."

If so, then Chicago's about to get its own "giddy sort of excitement." The Windy City is launching its own "Sunday Parkways" program, shutting down some main city streets for two Sundays in October. It's a first for the city.

NYC officials say they may continue the Summer Streets program if it's successful; Chicago likely would too.

It's an event that has taken off in some foreign cities -- including Bogotá, Colombia; Guadalajara, Mexico; and Paris -- as well as some smaller U.S. cities -- including, perhaps unsurprisingly, Portland, Oregon.

Is this the start of a new trend? Should more places in the U.S. start "carfree" weekends?