Through the first half of 2021, traffic on Illinois roads continued to climb, reaching levels northeastern Illinois normally experienced before the COVID-19 pandemic started. But increasing COVID-19 cases due to the Delta variant and resulting government restrictions since then again curbed travel in the region. Starting in mid-summer 2021, volumes for passenger vehicles declined somewhat and fell below pre-pandemic levels. Volumes for single-unit trucks, however, has followed an opposite pattern. Volumes for single-unit trucks, which typically serve a local market, are 15 percent above pre-pandemic levels.
Traffic volumes in 2021 still generally have increased substantially from winter lows, based on current statewide traffic data. By late June 2021, volumes for passenger vehicles and commercial tractor-trailer trucks reached pre-pandemic levels. Volumes for single-unit trucks consistently have remained above pre-pandemic levels since March 2021.
The winter lows were associated first with an increase in COVID-19 infections and the resulting restrictions on activity, but significant snowstorms this past February also constrained travel. A similar decrease-and-rebound trend has happened with traffic on the Illinois Tollway’s system.
Before this past winter, traffic volumes in 2020 steadily recovered from the early days of the pandemic. During the first two weeks of Illinois’ stay-at-home order in March 2020, average passenger traffic on arterials and expressways overseen by the Illinois Department of Transportation (IDOT) declined by almost 50 percent. Heavy truck (multiunit) traffic declined by 10 percent. Travel by single-unit trucks initially decreased somewhat more than heavy trucks.
But volumes for all trucks surpassed pre-COVID levels from late March into November 2020. During the summer last year, passenger vehicle volumes remained around 10 percent below normal levels before declining somewhat in the fall. The decline is consistent with past years since travel typically peaks during the summer.
Expressway speeds also are continuing to return to normal levels. This change is most apparent on IDOT expressways, which typically are more congested. During large portions of the day in September 2021, expressway speeds were at or near pre-pandemic levels. But travel in the early morning hours hasn’t been as congested on IDOT expressways. Reductions in travel speed during the early morning have not, yet, returned to normal levels.
Travel speeds still remain somewhat elevated on the Illinois Tollway’s system. Slowdowns still may happen in spots because of weather, crashes, or other incidents. But traditional morning and afternoon travel peaks slowly are returning, with the largest reductions in travel speed experienced during the late afternoon and early evening.