- Traffic density has risen by 6.3% on a national basis — with traffic increasing 8.2% over the past six years, while the miles of American roads have increased by only 1.8%.
- In Alaska, Tennessee and Texas, traffic density has increased the most, by 20.8%, 15.0% and 14.4%, respectively.
- Oregon’s traffic density has fallen 17.2%, and Nevada has seen traffic density fall 8.7% — largely due to new roads being built.
- Adding insult to injury, some states actually lost roads over the past five years. Rhode Island has 7.0% fewer roads than it did in 2012.
No. 1: Alaska
+20.8% traffic density
In Alaska, traffic density increased at more than three times the national rate. The main contributor to this drastic rise was the number of miles driven on Alaskan roads, which increased by 727 million — that's 15.2% growth.
No. 2: Tennessee
+15.0% traffic density
Compared to its neighbor Alabama, traffic density in Tennessee increased by 56.0% from 2012 to 2017. The total miles of Tennessee roads increased by only 0.5% despite a 15.6% increase in the number of miles driven.
No. 3: Texas
+14.4% traffic density
Texas' traffic density increase caused the state to jump five spots in the rankings of the worst states for traffic problems — from 22 in 2012 to 17 in 2017. Additionally, Texas traffic was 13.0% worse than the national average in 2017. This is surprising since Texas has the most miles of public roads of any state.
No. 4: Colorado
+13.8% traffic density
Colorado's roads are getting more use than ever in recent years. Roadway usage, measured as total miles traveled in the state, increased 14.1% from 2012 to 2017. Together with the fact that there was only a 0.3% jump in the total miles of public roads — which is 83.0% less than the nationwide figure — the increased road usage contributed to Colorado having one of the biggest traffic density increases during the span of this study.
No. 5: Georgia
+13.5% traffic density
Despite the fact that Georgia roadways were being expanded during this study, the state's substantial jump in roadway use was enough to rank it as the state with the fifth largest traffic density increase. In fact, Georgia's 16.0% jump in miles traveled from 2012 to 2017 was the third largest increase of any state, behind only Utah and New Mexico.
Roadway use increased by as much as 18.6% in some states
Utah saw the greatest jump in the number of miles driven. The state saw an increase of 18.6% from 2012 to 2017. This was 10.4 percentage points greater than the nationwide gain of 8.2% over this time period. At the other extreme, North Dakota saw a 3.6% drop in total miles driven — all the more surprising given that the state's population grew 8.0% during the same span.
Expanding roadways are not keeping pace with increased usage
Nationwide, roadway mileage has only increased by 1.8% and is outpaced by the usage increase of 8.2%. However, during the six-year span of this study, we found that some states dramatically expanded their roadways. The leader in this respect is Oregon, where the total length of public roads increased by 33.8%. That's 32 percentage points higher than the nationwide change. Contrarily, 11 states saw a decrease in public roadway miles. Rhode Island led this group, with a drop of 7.0% during the period we considered.
Increased traffic density can lead to higher auto insurance rates
Along with being frustrating for drivers, high traffic density can lead to greater car insurance costs. Anytime you have more vehicles driving in close proximity to each other, the likelihood of crashes increases. When this translates into more frequent auto insurance claims, insurers react by raising premiums. Some of the states with the highest average costs of car insurance also have some of the biggest traffic problems — including Rhode Island, New Jersey and New York.
Complete list of states
Miles driven difference
Miles of roads difference
Traffic density difference
ValuePenguin looked at highway data available from the Federal Highway Administration in 2012 through 2017 to determine in which states traffic has increased the most over the past five years. Mileage includes interstate, state and local roads, both urban and rural. Mileage includes both commercial and non-commercial traffic. Traffic density is measured by miles driven per mile of road in a given state.