station through Downtown Seattle and the Rainier Valley, and terminates at Angle Lake station near Seattle–Tacoma International Airport. Trains serve all downtown tunnel stations 20 hours a day every day; during regular weekday service, trains run roughly every six to 10 minutes during rush hour and midday operation, respectively, with longer headways of 15 minutes in the early morning and 20 minutes at night. During weekends, 1 Line trains arrive every 10 minutes during midday hours and every 15 minutes during mornings and evenings. Light rail service from Westlake to International District/Chinatown takes approximately seven minutes. Prior to the cessation of bus service in March 2019, the DSTT was served by seven bus routes that stopped at all four tunnel stations as well as stops near the former Convention Place station. At each station, bus routes were divided into three bays labeled with their general direction. Bay A was served by three routes heading north toward Northgate and the University District and east to Kirkland via State Route 520; Bay C was served by three routes heading south through the SODO Busway toward the Rainier Valley and Renton; and Bay D was served by a single route, Sound Transit Express route 550, heading east to Mercer Island and Bellevue via Interstate 90. During closures of the Downtown Seattle Transit Tunnel, tunnel buses were rerouted onto 2nd and 4th Avenues between Yesler Way and Pine Street, and Stewart Street and Olive Way between 2nd and Boren Avenues. Metro also runs a special route, the Route 97 Link Shuttle, between all Link light rail stations during service disruptions. Operations The DSTT is open for 20 hours on weekdays and Saturdays, from 5:00 am to 1:00 am the following day, and for 18 hours on Sundays, from 6:00 am to midnight. At the time of its opening in 1990, the Metro Bus Tunnel only operated from 5:00 am to 7:00 pm on weekdays and 10:00 am to 6:00 pm on Saturdays, with no Sunday service; the operating hours were temporarily extended into weekday nights from 1998 to 2000 at the request of the Seattle Seahawks and Seattle Mariners, but were cut after the passage of Initiative 695 and subsequent loss of motor vehicle excise tax revenue. Preparations for Link light rail service restored late-night and full weekend hours for the tunnel, introduced in June 2009 after Sound Transit Express route 550 moved all