The Moovit Public Transit Index has been tracking the impact of COVID-19 on public transit usage around the world. Not surprisingly, people are using transit a lot less.
Above is a chart from Moovit showing usage from January 15, 2020 to April 12, 2020, for a collection of US cities including San Francisco, Chicago, New York, Philadelphia, Seattle, and others. Early March is when usage started to really fall off, with most of the cities now sitting somewhere around 70-75% below January levels.
For the most part, the cities included in this chart have followed a similar trajectory. But there are a couple of outliers. Philadelphia doesn't seem to have fallen quite as much as other major US cities (-55.7% as of April 12, 2020). I'm not sure why. San Francisco looks to have "corrected" a lot faster. Perhaps because of an easier/quicker shift to working from home? And then there's Seattle.
The first confirmed US case of COVID-19 occurred in the Seattle area on January 21, 2020. Looking at the above chart (and implying causation), that single case appears to have had an immediate impact on transit usage. Over the subsequent three days, ridership dropped to -4%, -8.3% and then to -9.1%. Usage then remained consistently lower relative to all of the other cities in this index.
Was that it? Did Seattleite's behaviors really change that quickly? (And yes, I did have to look up the demonym for the fine people of Seattle.)
