Greg served as the environmental transportation planner for the Powell Street Promenade near Union Square.  In order to widen the sidewalks, the project included reducing the number of travel lanes from four to two; autos would have to wait behind stopped transit vehicles (cable cars).  This was unprecedented on a busy downtown street in San Francisco, but there was no other way to widen the congested sidewalks.  Greg delivered a comprehensive traffic analysis which demonstrated that a bottleneck would not result.  The project has been celebrated since its implementation in 2011, paving the way for similar lane configurations on other downtown streetscape projects, such as Folsom Streetscape.