CHICAGO (CBS) — A new study on traffic congestion shows, while drivers might be wasting more time sitting in traffic, it’s a sign of the continuing economic recovery since the Great Recession.

The latest annual study finds traffic has recovered completely since the economy tanked in 2008, and five of the 20 most congested roads in the U.S. are in the Chicago area.

The research by Texas A&M University found Chicago area traffic was the 8th most congested in the nation last year, consuming an average of 61 extra hours behind the wheel due to gridlock, construction, or accidents.

Co-author Bill Eisele said Washington, D.C., had the worst traffic; followed by Los Angeles, San Francisco, and New York. He said growing commute times are the result of more cars on the roads, a measure of an economy that has recovered from the Great Recession.

“If nothing is done to improve the transportation system, and everything stays the same, it’s clear that we can’t have goals of both high economic activity and low congestion,” he said.

Eisele said, unless the economy weakens, or infrastructure improvements are made, congestion only will grow worse.

“We project that, by 2020, the annual delay per commuter could grow from 42 hours that we saw in 2014 up to 47 hours in 2020,” he said.

The worst traffic headaches for the Chicago area were on stretches of the Dan Ryan, Eisenhower, and Kennedy expressways.