For More Information
- Can I download the report from the internet?
Yes. Link to: https://mobility.tamu.edu/umr/report/.
- What does “cost of congestion” mean?
Value of extra travel time (which we call delay) and the extra fuel consumed by vehicles traveling at slower speeds. Travel time has a value of $20.17 per person-hour and $55.24 per truck-hour in 2020. Fuel cost per gallon is the average price for each state.
- Why are some of the measure values different in this report compared to the previous UMR?
Some calculation procedures used for the 2021 report are different than in the 2019 report. The new procedures were used to re-calculate all of the historical values such that the delay and fuel amount and cost trend information is correct and can be compared over time.
- What is the Travel Time Index?
The ratio of the travel time during the peak period to the time required to make the same trip at free-flow speeds. A value of 1.30, for example, indicates a 20-minute free-flow trip requires 26 minutes during the peak period (20 minutes × 1.30 = 26 minutes). The Commuter Stress Index is the same as the Travel Time Index but is based only on peak direction travel only.
- Where should I look for national data and trends?
Look at the Summary Tables – National Congestion Levels and Trends.
- Where is the information about MY city?
Here’s the link: https://mobility.tamu.edu/umr/congestion-data/. There are multiple pages of trend data about your city. There is also a spreadsheet available for download with statistics for the 101 intensively studied areas as well as the remaining U.S. urban areas. Click on “Excel Spreadsheet” on this link: https://mobility.tamu.edu/umr/report/.
- How did you pick the 101 intensively studied urban areas?
We have all of the urban areas with more than 500,000 people. We have several smaller cities, mostly chosen by the previous report sponsors. This is not a representative list.
- Which one of these tables has the information that I need to know?
We strongly suggest that you examine all the measures. The Delay per Auto Commuter, Cost per Auto Commuter, and Travel Time Index are estimates of the congestion effects on individuals. Total Delay or Total Cost identifies the size of the congestion problem in the urban area. The change in values over time indicates the rate of growth or decline.
- Where does my city rank?
The city data tables show performance measure trends for several measures. Readers should compare ranking changes and performance measure values. In some performance measures a small change in the value may cause a significant change in rank from one year to the next. This is the case when there are several regions with nearly the same value (i.e., 15 hours is only 1 hour more than 14 hours). It is also important to look at trends. The multi-year performance measures are better indicators, in most cases, than any single year.
- What do you mean “There are several different rankings?”
There are several congestion measures and each has a use and a significance. There is no single, best measure. There are rankings for most measures.
- What happened to the Planning Time Index measure for 2020?
The PTI-95 is the reliability measure that uses the 95th percentile of the travel times to show the variability of the existing speeds. Due to a slight difference in how the speed data was compiled for the year 2020 and the effect this could have on the percentiles, it was decided to not produce the measure for the year 2020. The measure does exist for 2017 to 2019 in the spreadsheet available on the website.
- Which measure is used for the “four congestion years in one year” comparison?
The total hours of delay for each of the four time periods of the 2020 year are compared against the same time periods for the 2019 year. Based on the percentage of delay that is represented in 2020 for that period, a comparison is made against total delay in historical years to determine the nearest amount of total delay based on that percentage.
- Why were 2019 commuter levels used for the analysis of 2020 congestion?
2020 commuter information was not compiled at the time this report was generated and there was a great deal of discussion about who was using the roadways in the urban areas across the U.S. In order to show the sizeable difference in hours between 2019 and 2020, the 2019 commuter value was also used in 2020. If the actual number of commuters in each region was known, the hours per commuter would probably have been slightly higher in 2020 as the number of commuters on the roadways was probably down when comparing with 2019 commuters.
- How were 2020 traffic volumes generated?
The 2020 traffic volumes were not available at the time of this report. The 2019 traffic volumes were used as the basis and adjustments were made to them based on monthly traffic level factors from INRIX. These adjustments were made for each month of 2020 and the totals for each month were summed to get annual traffic volumes.
- What are the titles of the researchers?
Tim Lomax: TTI Research Fellow
David Schrank: Senior Research Scientist
Bill Eisele: Senior Research Engineer