Highway traffic congestion is not only time consuming, it’s extremely expensive.

A new study released by the American Transportation Research Institute (ATRI) on April 19th, showed that the snail’s pace drivers encounter almost daily on the nation’s highways is taking its toll on commercial drivers and their wallets.

The research indicates that by the study’s calculations, traffic congestion on highways drove operational costs for the trucking industry up by more than $49.6 billion in 2014. The calculations also showed that the impact of congestion costs on a per-truck basis amounted to an average of $26,625 for trucks that travel 150,000 miles per year.

Contributing to the high cost of sitting in traffic is the estimate of lost productivity of more than 728 million hours, equating to 264,500 commercial truck drivers sitting idle for a working year.

The month that incurred the most down time was July, followed closely by October, and the “congestion impacts” were mainly concentrated in urban areas, with 88% of the congestion costs concentrated on only 18% of the network mileage, and 95% of the total congestion cost occurring in metropolitan areas.

As one researcher said, the study shows that congestion is a “significant productivity drain” for the economy.