In May 2013, the SMART board approved a resolution designating the San Rafael to Larkspur link as its "preferred alternative". The agency submitted a letter to the Federal Transit Administration, and on September 24, 2013, SMART was accepted into its "Small Starts" program. The FY2016 Federal Budget included the funds to construct the Larkspur Extension under the Small Starts Program. Construction contracts were awarded to a joint venture of Stacy and Witbeck and Herzog Contracting Corporation at a cost of $36.3 million, and work commenced by late 2017 with an expected opening of late 2019. In April 2018, SMART was awarded a $22.5 million federal grant for the extension. Final costs for the extension are estimated to total $55.4 million. Train control and crossing system testing along the extension began in August 2019 and was completed by the end of October, whereupon driver training began. Revenue service commenced on December 14, 2019.