Potential impacts of the alternatives under consideration are presented in the AA/DEIS along with information on their benefits and costs. This document also proposes ways to avoid or reduce the possible impacts that could result from the alternatives under consideration. In addition, the AA/DEIS estimates the capital and operating and maintenance costs, the ridership, and cost effectiveness of each alternative. The AA/DEIS for the Purple Line follows the relevant FTA’s guidelines.

The AA/DEIS was available for public review for 90 days from October 17, 2008 to January 14, 2009. During this time, the Maryland Department of Transportation Maryland Transit Administration (MDOT MTA) held a series of public meetings and accepted and recorded public comments on the document and the project. The State of Maryland considered the public comments in making the decision on which alternative it selected. The Preferred Alternative was selected by Governor O'Malley in August 2009.