There is no universally accepted definition of traffic congestion. In reporting to the federal government, the states have in the past used peak-hour traffic volume-to- capacity (V/C) ratios, as calculated in the Transportation Research Board’s Highway Capacity Manual, as a congestion measure. Through 2009, the Federal Highway Administration (FHWA) summed these V/C calculations to determine the state mileage in various V/C categories. Since 2009, however, these tables have not been published by FHWA. Instead, FHWA has been reporting periodic statistics based on travel delays from mobile devices, but only for selected regions and roads, not for states.
The past two Annual Highway Reports use data directly from the INRIX Global Traffic Scorecard. This report uses 2020 congestion data. The metric selected was the “peak hours spent in congestion per auto commuter annually.” This measure is taken directly from the INRIX Scorecard and uses real-time traffic data. For 2020, Inrix defines “hours lost in congestion” as, “The total number of hours lost in congestion during peak commute periods compared to free- flow conditions.” (The INRIX data, which are computed only for selected cities, are extended to all U.S. metropolitan areas and then rolled up by state. See the Appendix for details.)
In 2020, the average annual peak hours spent in congestion in the urbanized areas across the United States was 23.83 hours (see Table 15, Annual Peak Hours Spent in Congestion per Auto Commuter, 2020, Figure 10). Annual peak hours spent in congestion range from 1.75 in Idaho to 86.14 in New Jersey. The congestion problem is primarily concentrated in the major cities of just a few states.
Between 2019 and 2020 overall congestion improved in 46 states and worsened in four. Commuters in 28 states spent fewer than 10 hours sitting in peak-hour congestion in 2020. Commuters in 17 other states spent less than 40 hours sitting in peak-hour congestion. Commuters in the bottom four states (New Jersey, Delaware, Illinois, and New York) spent more than 50 hours per year in traffic congestion.
Urbanized Area Traffic Congestion — Annual Peak Hours Spent in Congestion Per Commuter
|2020 Rank||State||Peak Hours Spent in Congestion per Auto Commuter|