by Michael Sivak, Sivak Applied Research.

In two recent analyses, I have shown that, during the pandemic, the decrease in vehicle miles traveled (VMT) in the states with preference for Democrats was greater than in the states with preference for Republicans. This was the case in both March 2020 (the first month with the pandemic) and June 2020. The present analysis examined whether the pattern was still present in July 2020—the month with the most current available data.

According to the Federal Highway Administration, in July 2020, VMT decreased by 11.2% compared with July 2019. However, the decrease in VMT varied widely by state, ranging from 27.3% in Hawaii to 3.9% in Arkansas. Thus, this analysis examined the relationship between the decrease in VMT in July 2020 in individual states (and the District of Columbia) and whether persons in those states were more likely to vote for the Democratic or Republican candidate in the upcoming presidential election.

The data on political preference in July 2020 came from the Cook Political Report that was published on July 24, 2020. The Report lists each state as Solid Democrat, Likely Democrat, Lean Democrat, Toss Up, Lean Republican, Likely Republican, or Solid Republican. In the analysis, the states were combined into three groups: Solid or Likely Democrat (N = 19), Lean Democrat, Toss Up, or Lean Republican (N = 12), and Solid or Likely Republican (N = 20).

The main result is that the average decrease in VMT in July 2020 in the states that were Solid or Likely Democrat was 14.1%, while in the states that were Solid or Likely Republican the decrease averaged 7.6%. (In the Lean Democrat, Toss Up, or Lean Republican states, the decrease was in between—11.2%.) The changes in VMT in each of the three months examined in this and the two previous analyses are summarized in the table below.

Although the states with preference for the Democratic presidential candidate tend to be more urban than the states with preference for the Republican presidential candidate, the urban/rural difference does not fully account for the main finding. This is the case because in July 2020 VMT on urban roads decreased by 12.3% compared with a decrease of 9.0% on rural roads—a smaller difference than the Democrat/Republican difference obtained in this analysis.

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