Spokane Street Bridge closures depressed West Seattle bike counts

View or duplicate this Google Sheet to check my math or explore the data yourself. Be sure to comment below if you discover anything interesting.

Bike trips across the Spokane Street Bridge (AKA the lower West Seattle Bridge) have followed a very different pattern compared to the Fremont Bridge, mostly due to extenuating circumstances around the emergency closure of the high bridge as well as multiple extended closures of the Spokane Street Bridge itself to maintain the unreliable swing bridge mechanism.

The biggest standout in this chart is the fact that bike trips in 2020 were barely down compared to 2019 even with all the stay at home orders and other measures to combat the COVID-19 pandemic. The Fremont Bridge saw a 40% year-over-year decrease in 2020, but the Spokane Street Bridge only saw an 11% decrease. But everyone in West Seattle knows all too well why this happened: The emergency closure of the upper West Seattle Bridge from March 2020 to September 2022. Biking came through clutch during this closure and helped alleviate some of the pressure on the few roadway connections that remained between the West Seattle peninsula and the rest of the city.

But within months of the high bridge reopening, the Spokane Street Bridge had emergency closures of its own. For longtime riders as well as those who picked up biking during the high bridge closure, the loss of the only direct bike connection toward the city center was a bit of whiplash. The late 2022 to early 2023 closure lasted a few weeks, followed by a series of subsequent shorter closures throughout 2023 and 2024 as SDOT crews got parts of the swing mechanism back into working order. More closures are coming in early 2025," but then that should be it for a while. Hopefully. We will post details about those closures when we get them, so stay tuned.

Note that this chart is missing the same data as the one above.

To make matters worse, there have been several weeks-long outages in which the Spokane Street bike counter was not operating. I have attempted to mark as many as I could find in recent years on the chart above. This missing data makes the charts even more difficult to decipher.

Even with missing data and the bridge maintenance closures factored in, bike counts over the Spokane Street Bridge are now trailing the Fremont Bridge in terms of catching up to each bridge's 2019 high point. It would likely take significantly more analysis to fully understand what is happening, but I've got a hypothesis. It is worth considering the mid-term and long-term impacts of closing the Spokane Street Bridge and its vital trail connection. The 2024 counts were depressed due to the multiple closures themselves, but I wonder whether people were somewhat less inclined to bike due to the uncertainty around the bridge. Riding up to find the bridge closed is a huge problem. There is no easy or safe detour, and it's not even clear how best to use transit to get across the gap once you're already at the closed gate. It's such a bad experience that it might be enough to deter people from choosing to bike in the future. After the final closure in SDOT's multi-year bridge rehab project is complete, the city may have some work to do to win back people's trust in this bridge.

People's transportation choices are about reliability, cost, convenience, and habits. Biking usually excels at the first two (and often the third, depending on the trip), but it takes work on each person's part to build up a biking habit. This is why extended highway closures can be such a boon to biking numbers like we saw in West Seattle during the Viaduct teardown and high bridge closures. People decide that rather than sit in traffic, they will take up biking. Then, once the road closure ends, a bunch of people keep biking anyway because they have established the habit and found it worthwhile. If this is true, then we have to consider the inverse may be true as well. If someone who used to be in the habit of biking is forced to drive or take transit while the Spokane Street Bridge is closed, they may just keep making trips by their new method even after the bridge reopens.

Though it may be difficult to accomplish in 2025 depending on how disruptive the upcoming closures are, the next goal should be to get back up to the 300,000 trips mark, which is where trips were in the years leading up to 2019. After the upcoming closures to replace the final swing bridge turn cylinder, the future looks bright for West Seattle and Duwamish Valley biking. In 2026, construction on the north segment of the E Marginal Way project will be complete, opening a new set of protected bike lanes that will connect the Spokane Street Bridge trail to a complete downtown waterfront bike route. There will be a fully-separated bike route from Alki Point and South Park to downtown and the Ship Canal Trail. Nothing like this has ever existed in Seattle before. These are exciting times. Just don't forget to make the appropriate sacrifices to appease the swing bridge hydraulic cylinder gods so that they may always remain in our favor.