6 1/2 Avenue is the formal creation of the NYC Department of Transportation based on the advocacy of Friends of Privately Owned Public Spaces (F-POPS, as founded by Brian Nesin, David Grider, Graham Coreil-Allen, and Jordan Zimolka). 

Our Arcade Parade drew attention to what we called Holly Whyte Way, a string of
Midblock POPS that run from 51st to 57th st, and in working with the DOT and Community Board, we convinced the city to install crosswalks, stop signs, and a mid-block crosswalk at 57th Street to mark the path.

This new "road", dubbed 6 1/2 Avenue, was the first modification to the city grid in decades, and puts pedestrians first.