The story of mode split in Boston.
If you were to look at the impact of Covid-19 on travel through the lens of overall movements, the story is pretty straightforward: a massive crash in March, with trip volume down over 50% across the country. Then a slow but steady recovery since, with trip volume about three-quarters of the way back to pre-pandemic “normal.”
But this high-level perspective obscures massive changes occurring in how people choose to travel — whether they choose to take trips by car, on the train, walking, or on a bike. As trip volume returns, new patterns are forming. And while these may be small decisions at an individual level, the collective change in how we move has a huge impact on our communities, from the level of congestion we experience and the amount of carbon emissions we produce, to the financial viability of public transit and the health of the businesses and restaurants in our neighborhoods.
To learn more, we took a look at the greater Boston area, which is served by the Massachusetts Bay Transit Authority. The MBTA offers multiple public transportation options to residents and visitors, including subways, buses, and commuter rail.
Prior to Covid-19, transit made up approximately 7% of all trips originating in the greater Boston area (~820,000 trips on an average weekday during the last week of February). During the first two weeks of March, as the earliest hints of the impact of the virus became visible, transit mode share dropped to just 5.4% of all trips (down to ~600,000 on an average weekday during the week of March 9). While many workplaces were still open and total trip count was flat, news of the virus may have caused some people to drive instead of ride — the 1.7% decrease in transit mode share was matched exactly by an increase in driving share (private auto and carpool) over the same period.
Throughout March, the rapid growth in Covid-19 cases and resulting shelter-in-place orders, as well as workplace and school closures, caused overall movements to plummet. Between the last week in February and the week of March 30, total trips in the greater Boston area fell 35% as average weekday trip volume fell from 11.7 million to 7.6 million.
All modes were impacted, but transit got hit the hardest. While driving trips fell to 7 million on an average weekday (a 33% decrease), public transit fell to only 97,000 trips, a massive 88% drop from the last week in February.
At the same time, greater Boston experienced a rapid increase in non-motorized travel, such as bike and pedestrian modes. When people did have to go somewhere (and the weather got nicer), they were getting outside. The share of all trips taken by car rose slightly, from 91% in the first week of March to 92.6% at the end of the month, where it remained at the end of April. However, trips were taken increasingly on foot and bike — these trips constituted around 2% of all movements (~270,000 average weekday trips) throughout the winter but increased to 6% (~450,000 average weekday trips) at the end of March.
Some of that increase in non-motorized trips was certainly due to the nicer weather, but it also reflected a change in where people were traveling to. At the peak of the lockdown period, average trip distance in the greater Boston area decreased from about 5.3 miles to 3.1 miles. At the same time, the proportion of all trips that started and ended in the same census tract increased from 30% to 55% of all trips.
Private auto and carpool trips have recovered to roughly 75% of normal pre-Covid-19 volume. At the same time, transit ridership is still a mere fraction of what it once was, with only 250,000 average weekday trips, about 30% of what the system saw at the beginning of the year.
This may be enough to bring back some regular road traffic, but with so many people still not commuting to work on a regular basis, it’s too early to tell if the huge surge in road demand that some cities feared would result from a rejection of public transit is going to emerge. Careful monitoring and innovative solutions will be necessary if transit ridership remains so low as more and more workers return to the office.
And while many planners may hope that Covid-19 might spur a new wave of walking and bike infrastructure, it seems those behaviors are already starting to wane — there were only 400,000 such trips on an average day last week (4.7% of total trips). Sustaining the increase in non-motorized transit, especially in a place like greater Boston with real winter weather, may require a significant investment in robust biking and walking infrastructure.
As people develop new habits, it will also be important to monitor the downstream impact on local businesses. If people are walking to the drugstore, they might go to the one in their neighborhood versus the one downtown. If they’re driving to work instead of taking transit, they might grab a coffee at a store by the freeway exit instead of one by the station.
As communities grapple with how to best support the economic health of their city, it will be critical for them to understand these trends and their implications in as near-real time as possible so that interventions and strategies can be developed to support the most promising changes — and mitigate those that might cause the most harm — before new patterns become the status quo.