Ridership Patterns for RapidRide F Line

King County Metro's RapidRide F Line travels inbound (westbound) from Renton to Burien, via the Westfield Southcenter mall and Tukwila International Boulevard Station. Outbound (eastbound) trips travel in the reverse direction. In October 2024, the F Line had 5,107 average weekday boardings.

F Line Map from King County MetroAverage Ridership Per Trip

The plots below show the average weekday ridership by stop in each direction, color-coded by time of day. For a more detailed breakdown of how the plots are set up, please refer to the How to Read the Plots section of the article discussing Route 70.

Average Weekday Ridership per F Line Trip: March 2024 to September 2024. Inbound" is toward Burien Transit Center; Outbound" is toward Renton. Click the plot to view at full-resolution in a new tab.

The ridership patterns for the F Line show a route with a few dominating stops connected by stops with minimal ridership.Some observations:

• The F Line's eastern terminus at The Landing in Renton has a few passengers board each inbound trip and alight each outbound trip. This stop is located on the east side of The Landing shopping center, next to an apartment building.
• On the west side of The Landing, the F Line stops at Logan Ave N & N 10th St. This stop provides convenient access to Boeing's Renton Production Facility and the many shops and restaurants at The Landing. This stop has some usage all day, with a noticeable spike in late night inbound boardings. This may be from Boeing employees who end their shift sometime between 10pm and 12am. Unlike most RapidRide routes, the F Line does not offer night owl service. The last inbound bus departs from The Landing at 12:01am.
• At Renton Transit Center, inbound trips primarily pick up passengers and outbound trips primarily drop off passengers. Inbound trips are busiest mid-day, while outbound trips are busiest in the afternoon. Renton Transit Center is conveniently located in downtown Renton near several apartment buildings, shops, and restaurants. Riders can transfer here between the F Line and routes 101, 105, 106, 107, 148, 160, 240, 153, 907, and Sound Transit routes 560, 566.
• West of the Renton Transit Center, the F Line travels along Rainier Ave and 7th St to serve various big box shops and grocery stores. Despite the auto-oriented development around these stops, each stop in this segment has a few riders per trip in both directions.
• At Tukwila Station (Tukwila Station Access Road & S Longacres Way), the F Line provides a direct connection to Sound Transit's Sounder service and Amtrak's Cascades train. As Sounder only runs in the mornings and afternoons, it is not surprising that F Line trips in both directions pick up passengers in the morning and drop off passengers in the afternoon. Amtrak Cascades has 12 total (6 per direction) departures from Tukwila Station each day.
• The F Line serves the Westfield Southcenter mall with the stop at Andover Park W & Baker Blvd. This stop generates significant ridership. Inbound trips primarily pick up passengers and are busiest in the afternoon and evening. Outbound trips primarily drop off passengers and are busiest in the mid-day and afternoon. Passengers can transfer here to routes 128, 150, 156, and 906.
• While the stops between Southcenter and Tukwila International Blvd (TIB) Station have minimal usage, this segment has the highest load of the route. Many passengers use the F Line as a connector between Link and the mall.
• TIB Station is the busiest F Line stop. This station is a Park & Ride with 600 spaces and also serves routes 124, 128, RapidRide A Line, and Link 1 Line. Inbound F Line trips drop off about 5-10 passengers and pick up 4-6 passengers per trip. Outbound trips have the reverse pattern as each trip drops off 4-6 passengers and picks up 5-10 passengers. While the area adjacent to the station has a few apartment buildings, the high F Line ridership at this stop is likely the result of passengers transferring from other routes.
• West of TIB Station, the F Line travels immediately north of SeaTac airport and through Burien. The stops in east and south Burien have some all-day ridership. The F Line stop at 4th Ave SW & SW 152nd St has decent ridership in the mid-day and afternoon in both directions. This stop is located in the center of Burien's commercial area.
• The F Line's western terminus is at Burien Transit Center. F Line trips are busiest in the mid-day and afternoon, but have strong ridership all day. Burien Transit Center is a Park & Ride facility with 488 parking spaces and serves King County Metro routes 131, 132, 161, 165, 631, RapidRide H Line, and Sound Transit Route 560. The transit center is located 2 blocks from downtown Burien and is near several mid-rise apartment buildings.

Daily Totals per Stop

The average daily total boarding and alighting counts show a similar pattern to the per trip data. Just four stops (Renton TC, Southcenter, TIB Station, Burien TC) account for the majority of the F Line's ridership.

Average F Line Weekday Boarding and Alighting Counts: March 2024 to September 2024. Inbound" is toward Burien Transit Center; Outbound" is toward Renton. Click the plot to view at full-resolution in a new tab.F Line Routing

Given the shared RapidRide branding, its easy for one to compare the ridership of the F Line with the ridership of other RapidRide routes. Before doing so, its important to acknowledge the role these routes play in the communities they serve. The F Line is unique among the RapidRide routes in that it connects distinct urban centers separated by areas with minimal development. A direct service between these cities is essential, but the geography limits the route's ridership and productivity because it has to travel through areas with lower ridership. In contrast, the A Line and E Line travel along mostly straight urban corridors and have much higher ridership and productivity.

Unfortunately, the F Line's ridership is further hampered by its indirect routing. As shown in the map at the top of this article, the route is relatively straight between Burien and TIB Station. East of TIB Station, the route continues straight on Southcenter Blvd before turning right (south) onto 66th Ave S. While Southcenter Blvd (SW Grady Way east of the intersection with Interurban Ave S) provides a direct route to Renton, the F Line takes a significant detour to serve two key destinations: Westfield Southcenter mall and Tukwila Station (Sounder/Amtrak). Given the strong ridership of the Westfield Southcenter mall stop, a detour to serve the mall is arguably worth it. Tukwila Station, however, hardly has the ridership to justify a longer detour all day.

Rerouting the F Line to run on Grady Way/Southcenter Blvd between Rainier Ave S in Renton and 66th Ave S (near Southcenter mall) would significantly speed up the route and increase ridership. The resources saved from the faster F Line routing could be used to operate a new route. This new route should be timed with Sounder and Cascades train departures and could run between Southcenter mall and Renton TC to serve Tukwila Station when needed. Alternatively, Metro may be expecting Sound Transit's upcoming S1 Line to handle the express trips along the F Line corridor, while the F Line handles shorter trips. As the S1 Line will not stop in Southcenter, riders traveling between Renton and Southcenter would still need to use the indirect F Line.

Looking Ahead

Metro has not indicated any significant changes are planned specifically for the F Line. Most of the region's transit focus has shifted to the Stride S1 Line.

Sound Transit is currently in the Design and Construction phases of the upcoming Stride S1 Line. When it starts operation in 2028, the S1 Line will be a highway-running BRT line between Burien and Bellevue, with stops at TIB Station, South Renton Transit Center, and NE 44th St. The S1 Line has the potential to nicely complement the existing F Line, offering express trips between Burien TC, TIB Station, and South Renton TC. South Renton TC is a new facility that will be built on the northeast corner of the intersection of S Grady Way and Rainier Ave S. This location is further from downtown Renton than the existing transit center, but provides better access to I-405 and I-167 for busses and drivers using the Park & Ride. Metro has not shared any restructuring plans for the routes that currently serve Renton TC. Unfortunately, Sound Transit has made several compromises with the S1 Line design that will increase travel times and reduce the overall utility of the line.