Traffic congestion has worsened as the economy improved, adding roughly 12 minutes a day to the average car commute, according to a report released Thursday.

That is 54 hours a year, almost as long as 18 languid baseball games or roughly the time it would take to binge-watch five seasons of a TV show.

The study from the Texas A&M Transportation Institute finds that deteriorating traffic is a consequence of the strong economy of the past few years. In most cities, more Americans at work means more cars on the road at peak times.

“The economy-congestion linkage is as dependable as gravity,” the report said.

Nationwide, congestion rose steadily from the 1980s through the middle of the last decade, before stalling briefly during the recession. Since 2009, it has grown by 26%, as measured by the number of hours commuters are delayed by traffic. That is equivalent to roughly an extra hour every year.