Lesson from the Rosslyn-Ballston Corridor: Easing Congestion by Raising the Residential/Non-Residential Mix, Kevin A. Zigadlo and Fred Costello, July 28, 2010

One of the reported effects of the use of TOD around Arlington's Metro stations over the last 20 years has been a relative (and, in a few cases, absolute) decline in traffic congestion along the Rossly-Ballston Metro corridor. In this paper, Reston Task Force member Fred Costello and an associate in his engineering consulting firm, Kevin Zigaldo, show how Arlington County eased traffic congestion along the Rosslyn-Ballston corridor over the last two decades.  Here is the bottom line:

...The graphs show why traffic has been improving:  over the years, the number of offices (in the Rosslyn-Ballston corridor) has been decreasing relative to the number of residences so more people are able to live near their work.  This improvement was made possible by requiring residential development to occur before or simultaneously with commercial and allowing a larger FAR for residential than for commercial. . . Because for the past 20 years the ratio of the added non-res-to-res has been 0.6, traffic has improved substantially.

 The full report is offered below.  Caution:  It's wonky!

 

033 an Analysis of the Rosslyn Ballston Metro Corridor--Zigaldo & Costello, July 2010