Over the past few weeks, people all around the world have been asked to drastically change their day-to-day behaviors in response to the COVID-19 outbreak. Social (or physical) distancing has been encouraged, and increasingly this distancing is enforced through stay-at-home orders and the closure of gathering places like businesses, museums, large event spaces, and parks. This event and the resulting economic effects will influence travel behavior due to changes in origins, destinations, modes, and routes. Since the way that policymakers respond to the crisis will play a considerable role in shaping the success or struggle of various transportation service providers, it’s important for them to consider how individuals might shift their transportation behaviors as a result of the pandemic.

A number of historical examples provide insight to the breadth of potential changes in transportation patterns, at least in the medium term, as a result of a significant event. Consider September 11, 2001. The Bureau of Transportation Statistics analyzed the effects of that event on transportation patterns and found the following trends in the time immediately following 9/11:

• Immediate and continuing reductions in air travel
• Immediate but temporary declines in highway travel
• No effects on rail travel
• Travelers switched from air to highway travel
• No considerable decline in business travel
• No decline in trips by older Americans
• No change in the percent of air travel by individuals in urban areas

Eventually, the economy and travel rebounded. U.S. GDP began to grow again in the fourth quarter of 2001. There was an increase in the number of trips taken over short distances (between 50 and 99 miles) for privately-owned vehicles, buses, trains, and ferries. Air travel surpassed pre-9/11 levels, but not until July 2004.

More germane to the current COVID-19 situation are the transportation patterns that manifested in the wake of the 2003 severe acute respiratory syndrome (SARS) epidemic. While that outbreak resulted in a smaller number of total cases and fatalities, it was estimated to cost the global economy $40 billion. According to the International Air Transport Association, air travel for Asia-Pacific airlines suffered a nine percent loss in annual revenue passenger kilometers immediately following the 2003 epidemic. Air travel rebounded to pre-outbreak levels after roughly seven months. With respect to transit, 75 percent of those surveyed in five European and three Asian countries affected reported avoiding public transportation as a precaution. A 2014 analysis pointed to a 50 percent decrease in daily ridership for Taiwan’s underground transit system during the peak of the epidemic there in March 2003. Transit ridership rebounded to pre-SARS levels in June 2003.

Of course, there are notable differences between the attacks on 9/11, the 2003 SARS outbreak, and the current COVID-19 outbreak. Experts anticipate the economic fallout from the current pandemic to be unprecedented, so it is important to consider that the full implications of the current situation cannot be anticipated at this point.

Similar to the two examples listed, the current pandemic has already produced considerable immediate shifts in transportation patterns. However, this time it is due to global instigation of social distancing practices. What is unknown is how long-lasting these effects will be, and whether patterns will return to business as usual.

Transportation choices and patterns are primarily influenced by two forces: societal factors and psychological factors. Societal factors represent forces that are external to an individual, for example the geographic, political, and economic forces that influence a person’s life. Societal factors encompass episodic events like public health emergencies or national security emergencies. Psychological factors represent how an individual’s motivations, habits, and emotions uniquely influence his or her behaviors.

Though we can’t currently anticipate the full effects, the following are three ways in which behaviors may change in the near and distant futures based on societal and psychological factors. In understanding the forces that contribute to a person’s transportation patterns, policymakers can better design effective policy strategies to facilitate a return to mobility.

Observed short-term shifts in transportation patterns
After the beginning of community spread of COVID-19 in the United States but prior to widespread work-from-home policies, many people still maintained their typical commute patterns. For example, turnstile entries into New York City’s MTA rail operations did not begin to fall until roughly one week after the first case of COVID-19 was reported in the City on March 1. With the shift to more individuals working from home just days later, commute patterns slowed to a near halt. On March 12, as more people began to voluntarily work from home, New York’s subways and buses each saw about a 19 percent decline in ridership compared to comparable dates in 2019. On March 24, when most people with non-essential jobs were working from home, ridership on the subway was down 87 percent compared to 2019.

Air travel patterns have generally mirrored this trajectory. On March 1, TSA checkpoint numbers roughly matched those of the same day in 2019. One week later, the number of people passing through checkpoints was about 15 percent lower than levels seen in 2019. By March 29, checkpoint pass-throughs were roughly 93 percent lower than the same day in 2019.

These downturns reflect societal forces as people are responding to mandates to work from home and to avoid travel. But before transportation was restricted or services cut and stay-at-home mandates were put in place, travel declines likely reflected individuals’ fears of exposure to the virus.

In the days leading up to widespread working from home, the opposite trends were seen for bikeshare systems. Ridership for bikeshare across the U.S. increased, with New York’s Citi Bike experiencing a 67 percent increase in trips between March 1 and March 11 compared to the same period in 2019, and Chicago’s system ridership doubling in the same period. These trends may reflect a desire for people to engage in a mobility option that doesn’t require close personal contact with others, as well as increased perceptions of safety with fewer cars on the road. While bikeshare ridership actually decreased in other cities, these decreases were not by the same magnitude. Ridership has since fallen since people are staying home.

Expected medium-term shifts in transportation patterns
When social distancing is no longer a requirement and personal mobility resumes in the immediate months following the lift of travel restrictions, transportation patterns may be slow in returning to pre-outbreak levels. Here again, societal factors such as a gradual re-opening of businesses will shape the immediate availability of transportation options.

In the wake of massive ridership declines, transit agencies have seen a reduction in farebox and sales tax revenues. For example, San Francisco’s BART system stands to lose around $57 million in monthly revenue if there is a continued 90 percent reduction in ridership and 50 percent reduction in economic activity. Especially among larger transit agencies that obtain a higher percentage of their operating revenue from fares compared to other sources, revenue losses could mean that it takes agencies that much longer to get service back up and running. If this results in unreliable service, it may take time for riders to regain trust in transit systems. With respect to air travel, the immediate drops in air travel can result in a number of ripple effects as the entire aviation industry responds to lower demand.

In both cases, if service is slow to rebound to pre-outbreak levels, the public may lose confidence in aviation and transit systems. On top of this, psychological factors like fear of exposure to the virus may also shape individuals’ willingness to return to these shared modes of transportation. In an early March survey, 48 percent of Americans indicated that riding public transit poses a high health risk due to the virus. Two-thirds of respondents did indicate they believed that airports and airlines were taking appropriate precautions, but 25 percent said they did not believe that any company associated with travel (inclusive of aviation and mass transit) were taking the appropriate steps to reduce risks.

Post-9/11 psychological research has indicated that fear can lead to higher perceptions of risk and increased precautionary behaviors. Air travel declined in the immediate months following 9/11 due to national security fears, but policy changes in transit (e.g. technical assistance, emergency preparedness, improved direct communication with agencies) and aviation (e.g. the creation of the Transportation Security Administration) have made these modes more secure and increased public confidence.

On the opposite end of the spectrum, it’s possible that there will be a surge in travel as people look to celebrate the ability to gather with friends and family again. Many of the large events and conferences that were postponed may be rescheduled. In China, transportation services are beginning to return in the aftermath of the outbreak. Yet the country is still grappling with the economic fallout of the outbreak with many citizens now unemployed, so mobility is likely to be affected for the foreseeable future.

Potential long-term shifts in transportation patterns
It is difficult to speculate on the precise effects the current pandemic will have on transportation systems over the long run. With respect to societal factors, not only will systems need time and resources to return to pre-outbreak levels of service offerings, but some services may never fully rebound. For example, newly-listed companies such as ridehailing services, venture capital-funded shared micromobility (i.e. scooters and electric bikes), and carsharing services, may find a post-outbreak economy inhospitable for their business models. Many of these companies were already struggling prior to the outbreak. Especially in the case of ridehailing, the workers themselves may be especially hard hit.

 For those whose work is primarily computer-based, those jobs have shifted to telecommuting during this period of social distancing. While most of these jobs will resume in-person when it is safe for people to reconvene, some employers may choose to offer flexible work arrangements on a more regular basis.

From a psychology perspective, current fears may last long into the future. While air travel patterns for the most part rebounded months after 9/11, a survey ten years after the fact indicated that 24 percent of Americans were still less willing to fly on airplanes. Fears about coming in close contact with others may especially reduce individuals’ willingness to take shared modes.

Lingering fears of shared transportation modes may direct people to other modes. Some bike shops have begun to see increases in sales and repairs. The mere act of purchasing or repairing a bicycle may serve as enough of a commitment to push some to longer-term behavior change.

Investing in a bike is also a more affordable option than buying a new automobile. Car sales have decreased compared to last year, with auto analysts expecting the decline in sales to continue. Still, those who already own vehicles may begin to drive for local trips they would have otherwise taken on transit or longer-distance trips for which they would have otherwise flown.

Policy implications
While the long-term effects of the novel coronavirus on transportation are still unknown, the crisis is already affecting the way people move around in the immediate term. Transportation providers should begin thinking about contingency plans for unknown outcomes. Understanding shifts in underlying behaviors is an important first step in planning for those future outcomes.

Though travel has been limited to the detriment of the economy, there have been positive indirect effects like better air and noise quality, improved roadway safety, and reduced emissions. In the midst of this crisis, we may see renewed pushes to enact policies and urban planning tactics that can maintain these benefits. Increasingly, there are calls to shut down streets so pedestrians and bicyclists have space. While temporary, this could create demand for permanent street closures.

The traveling public may be more inclined to take communal transportation modes like transit, airplanes, or shared services (e.g. ridehailing or bikeshare) if they feel that the authorities or companies providing those services have taken the appropriate precautions. This may mean that service providers need to allocate higher portions of their budgets toward cleaning supplies and campaigns that inform the public of health measures taken.