by Michael Sivak, Sivak Applied Research
Among the variables included in my ongoing monthly monitoring of key transportation indexes are passenger miles for domestic flying and total road vehicle miles traveled. That monitoring has shown huge pandemic-related drops in each transportation mode during the spring of 2020 and gradual rebounds (steeper for driving than flying) later in 2020 and in 2021. However, the underlying data for that analysis, for both flying and driving, are published with some lags. Therefore, the latest data for flying in my monthly monitoring are for August 2021 (down by 15% from August 2019), and the latest data for driving are for September 2021 (down by 1% from September 2019).
However, two related variables are published with minimal delays: the daily number of TSA screenings (with a delay of one day), and the weekly miles traveled on interstate highways (with a delay of three days). Consequently, this brief analysis compares the number of TSA screenings and the number of vehicle miles traveled on interstate highways during the week of November 8-14, 2021, with the corresponding week in 2019. The results, adjusted for population, are shown in the table below.
|Parameter||Change from 2019 to 2021|
|Driving on interstates by all vehicles||+3%|
|Driving on interstates by passenger vehicles||0%|
Michael Sivak is the managing director of Sivak Applied Research and the former director of Sustainable Worldwide Transportation at the University of Michigan.