by Michael Sivak.

This analysis was conducted to examine changes in traffic volume on rural and urban roads in the United States from 1991 through 2016. The raw data for the analysis were lane length (which takes into account all roadway lanes of travel) and distance traveled, both from the Department of Transportation. The average daily number of vehicles per lane was the calculated measure of traffic volume. The results are shown in the table below.

Click on table to enlarge.

Lane length. Rural lane miles during the period from 1991 through 2016 showed a generally continuous decline totaling 6%, from 6.405 to 5.992 million miles. This decline is due primarily to the ongoing urbanization of the United States. In contrast, urban lane miles during the same period increased by 62%, from 1.683 to 2.719 million miles. (The total number of lane miles—rural plus urban— increased by 8% from 1991 through 2016.)

Distance traveled. Rural vehicle miles traveled (VMT) increased from 884 billion miles in 1991 to 1,127 billion miles in 2002, an increase of 27%. This was followed by a decrease of 18% to 921 billion miles in 2014, and then an increase to 950 billion miles in 2016, or 7% higher than in 1991. In contrast, between 1991 and 2016, urban vehicle miles traveled showed a generally continuous increase totaling 73%, from 1,288 to 2,225 billion. (The total vehicle miles traveled—rural plus urban—increased by 46% from 1991 through 2016.)

Traffic volume. The average daily number of vehicles per lane on rural roads increased from 378 in 1991 to 491 in 2002, for an increase of 30%. This was followed by a decrease of 15% to 415 in 2014, and then an increase to 433 in 2016, for a total increase of 15% since 1991. In comparison, the average daily number of vehicles per lane on urban roads increased from 2,098 in 1991 to 2,373 in 2000, for an increase of 13%. This was followed by a decrease of 11% to 2,123 in 2013, and then an increase to 2,236 in 2016, for a total increase of 7% since 1991.

The results of this analysis indicate that the recent changes in traffic volume on rural and urban roads showed similar patterns, but the changes were more pronounced on rural roads. Specifically, traffic volume on both types of roads increased from 1991 to the early 2000s, followed by a decrease through the early 2010s, and an increase since then. Overall, from 1991 through 2016, traffic volume has increased about twice as much on rural roads than on urban roads (by 15% and 7%, respectively).

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