The Surprising Efficiency of RapidRide A
Every year, King County Metro provides statistics on their bus services in their System Evaluation, available online. One measure that is presented for all regular bus routes is Rides per Platform Hour. It answers a core question: how many people does this route serve for each hour a bus spends driving it?" Using this measure, King County Metro can assess the time efficiency of routes and make choices on future service.
Which route performs the best at Rides per Platform Hour? You might be surprised. One might guess that the most time-efficient route would ply the densest parts of Seattle, where there is the highest concentration of riders. But this would be incorrect. In fact, the best performing route on this measure is RapidRide A, which connects Federal Way to Tukwila along Pacific Highway South (SR99). Not only does it have the most Riders per Platform Hour at both peak and off-peak weekday times - that means Monday through Friday, 5 am to 10 pm - it also performs well on nights and weekends. Altogether, RapidRide A serves 7,116 rides per weekday, which is 4th among all Metro bus routes.
| Day | Period | Rides per Platform Hour | Rank among Metro bus routes |
| Peak (5-9am, 3-7pm) | 36.8 | 1st | |
| Weekday | Off-Peak (9am-3pm, 7-10pm) | 33.1 | 1st |
| Night (10pm-5am) | 29.5 | 2nd | |
| Saturday | All Day | 28.4 | 4th |
| Sunday | All Day | 26.3 | 5th |
I took a drive down Pacific Highway at Saturday noontime to witness this unsuspecting ridership champion. As I drove south from Tukwila, I quickly reached the airport. Nearby, leafy hotel plots and office parks flanked the road. On this bright but overcast day, there were plenty of people out-and-about, walking on the sidewalks. Probably out-of-towners," I thought, off on a lark from their hotels. But I was surprised to see that the pedestrian traffic sustained even once I had gotten beyond the airport. People were walking the sidewalks on either side of the seven-lane highway. What was fascinating to me was the seeming contradiction between the built environment and what I perceived on the ground: the amount of people that travel through the area on foot or transit.
Most of South King County is zoned in the suburban pattern of separating residential from commercial land uses and multifamily housing from single-family housing. The few areas for mixed uses are often concentrated on busy roads, like Pacific Highway. There are significant downsides with placing mixed uses on busy highways. For one, these stroads" are unsafe. In cities in South King County, pedestrian fatalities have almost tripled in the past decade, according to the Urbanist and Washington State DOT. In addition, development that stretches along busy roads tends to be less compact overall, which means longer walks for pedestrians. This is particularly a problem in places of low income, where the average person is less likely to have access to a car. The success of RapidRide A consists largely in serving this challenging development pattern efficiently.
RapidRide A runs through the longest corridor of moderate walkability in south King County. (Map credit to Google Maps and WalkScore)First, the direct routing of the A on Pacific Highway works in its favor to make it both useful and fast. The suburban development pattern described above, though posing significant costs to pedestrians, concentrates diverse uses on a continuous corridor. Pacific Highway is the longest corridor with reasonable foot access to services in south King County (as can be seen in a WalkScore map of the area). By serving this entire corridor, the A connects many destinations where people may need to go, and its arrow-straight routing saves time that could be lost on turns and detours.
The A is also aided by the technological and infrastructure amenities associated with RapidRide service. Off-board fare payment speeds boarding. The route uses Business Access and Transit (BAT) lanes that extend for most of the corridor and seem to remain reasonably clear of traffic. RapidRide A stops about every 2,000 feet, compared to a typical local bus, for which about 1,200 feet is common. It may mean longer walks for passengers, but the entire corridor is still accessible with a quarter-mile walk or less. Meanwhile, fewer stops mean higher speeds and greater reliability.
The southbound 176th St Station, near Link and SeaTac Airport. All RapidRide A stops allow off-board payment; many stations have real-time arrival signs. (photo by author)As a result of these factors, the bus can get travel its 10.9 mile route in 42 minutes at noon time. For comparison, the 7" - a local route - takes 41 minutes to travel 6.4 miles down Rainier and Jackson - a 40% slower average speed. Overall, RapidRide A provides a service that is speedy enough to compete with driving. It goes directly where people need to go, and its strong ridership and productivity statistics throughout the week attest to its usefulness. It seems undeniable that the A makes Pacific Highway a more walkable, productive, and vibrant place than it would be otherwise.
With continued investments in traffic safety and transit, hopefully RapidRide A can continue to fulfill people's transportation needs for years to come. RapidRide A is itself an example of a smart investment. When it began in 2010 as the first in the RapidRide program, it took advantage of existing HOV lanes on SR99 and the connection to the then-new Central Link light rail. 13 years later, its success continues to provide lessons to transit planners and advocates on how to invest in effective transportation. Soon, another investment will reshape the area: the Federal Way Link extension is currently scheduled to finish in 2025.
The S 180th St RapidRide A station in SeaTac, WA. (photo by author)