New data shows traffic congestion declined by 30 per cent last year as gas prices and a lacklustre job market saw fewer drivers on U.S. roads.

Data firm INRIX looked at traffic patterns from the 100 largest urban centres in the country. Of those, 70 cities saw gridlock ease, it got worse in 30 cities. Overall, the decline was the largest the agency has seen since 2008, when the U.S. economy was plunging into recession.

"The declines in traffic congestion across the U.S. and Europe are indicative of stalled economies worldwide," INRIX president Bryan Mistele said.

"In America, the economic recovery on Wall Street has not arrived on Main Street. Americans are driving less and spending less fuelled by gas prices and a largely jobless recovery," Mistele said.

The large dropoff came after two years of modest gridlock increases in 2009 and 2010, at one and 10 per cent, respectively.

Gas prices, joblessness factor into congestion

The INRIX numbers released Tuesday do not include Canadian data, but within the U.S. specifically, they do show interesting trends.

Cities where employment growth outpaced the national average — such as Tampa, Austin and Houston — saw some of the largest increases in traffic congestion. On the flip side, cities including Los Angeles, San Francisco and Honolulu that have some of the highest gas prices in the country saw their traffic congestion figure decline precipitously.

In 2011, only 890,000 of the 2.6 million new jobs the U.S. economy created were in the nation’s largest urban centres. Cities are still down six million of the nine million jobs lost during the recession.

"Lack of employment combined with high fuel prices is clearly driving the decline in traffic," the report said.

Nationwide, motorists in the country's worst driving corridors waste some 60 hours a year in traffic.

Overall, in terms of congestion, Honolulu was ranked worst, while Worcester, Mass., was rated the best.

INRIX found that the worst day overall for traffic is Friday and the best day is Monday.