In this post, I take a look at bicycle traffic patterns in Seattle, Washington, in light of the ongoing COVID-19 pandemic. Also, given very recent events and the timing of this article’s publication, I take the opportunity to include updated data for June, which presents bicycle traffic patterns affected by the recent social protests in addition to the pandemic. The data supporting this analysis was sourced from the Seattle Department of Transportation Bike Counters webpage, which registers daily bicycle traffic at 12 locations throughout the city. The original analysis was inspired by an R for Data Science Tidy Tuesday community event on GitHub; I highly recommend checking out the Tidy Tuesday repository for interesting, quick, data challenges.
Seattle Bike Traffic Overview
First, let’s take a look at an overview of tracked Seattle bike traffic over time.
A few high-volume crossings (e.g., BGT North of NE 70th and the Elliot Bay Trail) stand out as well as some gaps in the bike counter data. We lost access to the X39th Ave NE Greenway counter in mid-2018 with no visible return. There is also clear seasonality to this data, as might be expected given Seattle’s rainy winters. Using NOAA weather files for the area, we can take a quick look at the relationship between the number of bicyclists on the road and area precipitation. We consider a “rainy” day to be one with at least 0.5 inches of precipitation.
We can see a relationship between precipitation and bike count as well as a relationship between temperature and bike count. Bicyclist counts are noticeably higher on sunny, dry days than cold, wet ones. In Seattle, rainy day bicyclists are likely regular commuters.
Next, let’s look into the hourly bike traffic patterns at different crossings to get a sense of their usage.
Note: This graphic was inspired by a live screencast by David Robinson. Check out his YouTube channel for more Tidy Tuesday analyses.
Many bike crossings show clear commuter patterns on the weekdays, with ridership hitting its highest counts around 9 am and again at 5 pm on Monday through Friday. For most crossing locations, weekend traffic peaks around noon.
COVID-19 and Bike Traffic
Seattle was the first major U.S. city to be affected by COVID-19 starting in February, 2020. How have the imposed social distancing practices impacted overall transportation trends over the past months? First, let’s look at the overall growth in COVID -19 cases compared to daily bike traffic.
With pandemic isolation practices in place, there appears to be a cyclist traffic peak in April and early May. In late May and June, we start to see a decrease in these cyclists as businesses begin to reopen.
How, then, has the pandemic impacted commuter patterns?
As the pandemic worsens, we see a loss of commuting structure to the bicyclists’ movements over the course of the day. By April, the transportation pattern differs significantly from previous years, with counts peaking in the afternoon.
Finally, let’s look at these cycling patterns broken out by counter location for the month of April, in comparison with average April ridership patterns from 2014 through 2019.
These quick snapshots of Seattle’s bike lane traffic show a changing picture of transportation in the midst of a pandemic. As social distancing practices make public transit or ride-hailing inadvisable modes of transportation, many people turn to biking for both necessary transportation and leisure activity.
Local Social Protest Activities and Bike Traffic
Seattle was also the site of some of the nation's largest organized social protests in response to the May 25th death of George Floyd. Notably, the Capitol Hill Organized Protest (CHOP) created and occupied an autonomous zone for several weeks in June within Seattle’s Capitol Hill neighborhood. One of the bike counters we studied in this analysis, the Broadway Cycle Track N of E Union Street, is located on the edge of this zone, providing a unique look at movement during this time.
As the community responds after the death of George Floyd on May 25, 2020, we see a sharp drop in cyclist movement near this counter. When the autonomous zone is established on June 8, 2020, movement falls close to zero. Unfortunately, we can’t see the full picture with regards to pedestrian data at this location and time. However, the bike data shows a clear change in movement patterns and gives an indication of the major impacts of this event.
Events of the past several months have been unprecedented in scale and scope, with tangible effects on the micro- and macro- level. Changes at each level may provide valuable insight into the impact of events throughout the world. How have COVID-19 and social protests impacted transportation patterns in your neighborhood? Have you seen follow on effects outside your community? Share your comments below or in the CANA Forum.
Lucia Darrow is an Operations Research Analyst at CANA Advisors. If you would like to learn more about Lucia and CANA Advisors’ upcoming courses in analytics or the CANA Foundation, please contact her at firstname.lastname@example.org