from August 1989 to September 1990, with regular bus service beginning on September 15, carrying 28,000 daily passengers in its first year of operation. For the next several years, until June 2004, service in the tunnel was provided exclusively by dual-mode buses, which ran as trolleybuses in the tunnellike the city's extensive trolleybus systemand as diesel buses on surface streets and freeways. The tunnel was closed on September 24, 2005, for modification to accommodate both buses and Sound Transit's Central Link (now the 1 Line) light rail trains with shared lanes and platforms. The roadway was lowered by and other improvements were made to prepare for light rail service. New hybrid electric buses were moved into the tunnel to replace the Breda fleet, as the overhead wire was replaced for light rail trains. The tunnel reopened on September 24, 2007, and light rail service began on July 18, 2009. A stub tunnel, branching from the main tunnel, was constructed under Pine Street to allow light rail trains to stop and reverse direction; it was later used as the first segment of a light rail extension to Capitol Hill and the University of Washington that opened in 2016. Convention Place station was closed permanently on July 21, 2018, to make way for an expansion of the Washington State Convention Center that would also restrict bus access to the tunnel. On March 23, 2019, bus service in the tunnel ceased and its remaining seven routes were moved to surface streets. Route and stations The , tunnel is used by the 1 Line between Westlake and International District/Chinatown stations. Entrances at several tunnel stations are built into nearby buildings with variable-message signs over the stairs and elevators leading to the mezzanines. A total of 11 wheelchair-accessible elevators connect the tunnel stations to the surface. The deepest of the tunnel stations are below street level and consist of two side platforms, two tracks, and a former bus passing lane in the middle. Since 2019, the stations have also had signs with numbered exits to aid in rider wayfinding. As part of the city's public art program that began in 1973, the Downtown Seattle Transit Tunnel and its stations were furnished with $1.5 million (equivalent to $ million in dollars) in artwork by 25 artists commissioned by King County Metro. The northern portal, formerly accessible to buses at street level from Olive Way, and from