The Downtown Seattle Transit Tunnel is a 1.3-mile tunnel under downtown built in 1987 to relieve bus congestion along surface streets. The tunnel was retrofitted from 2005 to 2007 to accommodate light rail, and in 2009, Link light rail trains began serving tunnel stations as part of the initial Central Link segment. All tunnel bus routes were rerouted to surface streets in 2019 to make way for the demolition of Convention Place Station, making the tunnel an exclusive subway for Link trains within the city core. Above the tunnel, 3rd Avenue through downtown serves as a major bus arterial, with access restricted to buses only during peak commuting hours.