by Michael Sivak, Sivak Applied Research.

In this brief note, I examine the distances traveled by flying and driving in the United States in March and April 2020—the first two months of the current pandemic—and compare them with the corresponding distances in March and April 2019. The raw data for the analysis came from the Bureau of Transportation Statistics (revenue passenger miles flown on all scheduled domestic flights) and the Federal Highway Administration (vehicle miles traveled). The results are shown in the table below.

The main findings are as follows:

• The decrease in travel in both months was substantially greater for flying than for driving.

• The decrease in travel was substantially greater in April than in March; flying in April was down about 96% and driving was down about 40%.

Two caveats are in order. First, the measure used in this analysis for driving—vehicle miles traveled—includes travel not only by personal vehicles (cars, light trucks, and motorcycles), but also by medium and heavy trucks and buses. Thus, this measure also includes travel for road-based freight transport and road-based public transport. On the other hand, the flying measure—revenue passenger miles flown—does not include freight or public transport. However, vehicle miles traveled by cars, light trucks, and motorcycles typically account for a vast majority of travel (90% in 2018). Therefore, the inclusion of medium and heavy trucks and buses is unlikely to have substantially influenced the findings.

The second caveat is that the flying measure involves passenger distance traveled, while the driving measure involves vehicle distance traveled. If the average number of occupants per road vehicle has not changed from early 2019 to early 2020, then this would be of no consequence. On the other hand, if the number of occupants has decreased, the reduction in occupant distance traveled would be larger than shown. Conversely, if the number of occupants has increased, the reduction in occupant distance traveled would be smaller than shown.

Michael Sivak is the managing director of Sivak Applied Research and the former director of Sustainable Worldwide Transportation at the University of Michigan.