M Ocean View

In 2010, Muni replaced the rail junction just south of St. Francis Circle station. Rail service south of West Portal station was replaced with buses from May 17 to September 4.[7][8]

The line was temporarily replaced by buses from June 25 to August 24, 2018 due to the Twin Peaks Tunnel shutdown.[9] During that time, a new traffic signal with transit signal priority was installed where the line crosses the northbound lanes of 19th Avenue at Rossmoor Drive, and red transit-only lanes were painted to indicate that drivers must not block the crossing.[10]

On March 30, 2020, Muni Metro service was replaced with buses due to the COVID-19 pandemic.[11]

Rail service resumed on August 22, 2020, with the routes reconfigured to improve reliability in the subway. M Ocean View and T Third Street service were interlined, running between Sunnydale station and Balboa Park station.[12] Rail service was re-replaced with buses on August 25 due to issues with malfunctioning overhead wire splices and the need to quarantine control center staff after a COVID-19 case.[13]

M rail service resumed on August 14, 2021 – again terminating at Embarcadero, as the K and T are again interlined.[14]

The M Ocean View begins service at 5 a.m. weekdays, 6 a.m. Saturdays and 8 a.m. Sundays, with the end of service occurring around 12:30 a.m. each night. Daytime headways are 10 minutes on weekdays; Daytime headways are 12 minutes on weekends.[15][16]

Service on most of the route is provided by overnight Owl buses during the hours that rail service is not running. The L Owl serves the portion between Embarcadero and West Portal, and the 91 Owl serves the portion between West Portal and SF State. On weekends, M Ocean View Bus service runs from 5am until the start of rail service. The bus line largely follows the rail line, but it uses surface streets to parallel sections where the rail line has dedicated rights-of-way.[17]

19th Avenue/ M Ocean View Project
Twin Peaks Tunnel West Portal West Portal and 14th Avenue St. Francis Circle Ocean (optional) Eucalyptus Stonestown Galleria SF State rerouted to Embarcadero via Balboa Park Parkmerced (planned) future extension to Daly City

M Ocean View moves at only 8.5 to 9.5 miles per hour (13.7 to 15.3 km/h) during afternoon commute hours over a 2-mile (3.2 km) distance along 19th Avenue/Highway 1. The slow speed is attributed to trains stopping at multiple busy street crossings.[18] In addition, the majority of riders access 19th Avenue stops from the west side of 19th, since Stonestown Galleria, San Francisco State University and Parkmerced are all located west of 19th. In order to access the stops, which are located in the median of 19th Avenue, pedestrians cross three lanes of traffic and a turn lane. In San Francisco, 55% of severe and fatal pedestrian accidents occur on 7% of its street miles, which includes the 19th Avenue/Highway 1 corridor.[19] In response, the San Francisco County Transportation Authority published studies in 2010[20] and 2014 which explored options to facilitate pedestrian access and improve travel times.[18]

The full-subway option was chosen for further development and named the Muni Subway Expansion Project (MSXP).[21] Under the preliminary concept for MSXP, the rail line would remain underground past West Portal station. K Ingleside would branch off from the underground line and surface on Junipero Serra Boulevard just south of Saint Francis Circle. M Ocean View will remain underground along the current right of way under West Portal Avenue and 19th Avenue, branching off at Holloway to Parkmerced. The underground line would continue with J Church service along 19th until surfacing just east of the intersection of 19th and Junipero Serra, then continuing on to Balboa Park via Randolph, Broad, and San Jose.[22]

The current West Portal station will most likely have to be redesigned as a two-level station with the J/K/M lines on the lower level and the L line on the upper level. New underground stations would be constructed at Saint Francis Circle (J/K/M lines), Winston Drive (J/M, serving Stonestown), Holloway (J/M, serving SF State), and Parkmerced (M). A potential infill station could be constructed at Ocean Avenue in Lakeside Village. Several existing surface stations would be removed; in most cases, they would be replaced by underground stations except for the Ocean View, Merced Heights, and Ingleside stop near Junipero Serra and 19th.[22]

The proposed full subway line would continue past Parkmerced with a long tail track; that tail track may be extended in the future to connect to the Daly City BART station via the M line. The total cost of the full subway line project is estimated at approximately $3 billion.[22]