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Tennessee had the highest-quality roads in the US in 2020, with 94.6% of roads classified as “good” — only 5.4% of the state's roads are in poor condition.

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The US Department of Transportation (DOT) collects road quality data reported by states and quantifies it using the International Roughness Index (IRI). The IRI measures how many inches of vertical movement a passenger vehicle experiences while traveling one mile at 50 miles per hour.

A higher score means a rougher road: Roads with an IRI of less than 95 inches per mile are classified as “good,” roads scoring from 95–170 are “fair,” and roads above 170 are “poor.”

Which state has the worst roads?

As of 2020, Rhode Island had the worst roads of any state, with 48.1% of its road miles classified as “poor” by the Bureau of Transportation Statistics. And its roads aren’t improving; the percentage of “poor” road miles in Rhode Island increased by 33.3% from 2000 to 2020.

New Jersey and Hawaii had the next-highest percentages of “poor” road miles, with over 40%. New Mexico and California followed at 34% and 33%.

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Nationally, the percentage of roads in “poor” condition varies by state from 5.4% to 48.1% depending on the state.

Which state has improved its roads the most?

Arkansas improved its road conditions the most over time, decreasing the percentage of its “poor” roads from 34.8% in 2000 to 8% in 2020. Oklahoma also improved its conditions, decreasing its percentage of “poor” roads from 31.8% in 2000 to 6.3% in 2020.

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Measuring Pavement Roughness
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