Traffic congestion is a major drag on the city’s economy, costing the metro area a projected $20 billion a year for the next five years, according to a report commissioned by the Partnership for New York City, which represents large private sector employers.

That’s significantly more than the estimated costs of traffic congestion in December, 2006, when the Partnership estimated the annual loss at $15.9 billion in today’s dollars.

A new fact sheet released by the Partnership says that, without congestion pricing to thin out traffic, commuters in the five boroughs and surrounding counties will lose the equivalent of $9 billion annually in travel time.

Businesses stand to lose nearly $6 billion in revenue and $2.4 billion in increased operating costs a year, according to the Partnership, and the region will lose $2.5 billion to excess fuel and vehicle operating costs.

The Partnership prepared a similar report ahead of Mayor Michael Bloomberg’s congestion pricing plan, which was smothered behind closed doors 10 years ago by Assembly Democrats led by former speaker Shelly Silver.

At the time, the Partnership estimated that traffic congestion cost the region $13 billion annually, or $15.9 billion adjusting for inflation.

Since then, traffic has gotten worse while people’s time has grown more valuable. “The cost of excess congestion has grown more rapidly than inflation primarily due to increased time spent commuting and for work-related travel, increased wages, and increased operating costs overall,” a spokesperson said via email.

Governor Cuomo is expected to unveil his congestion pricing proposal tomorrow. The governor’s statements about the content of the plan so far have been highly ambiguous and subject to interpretation.

Meanwhile, as the transit system collapses and the city he runs chokes on gridlock, Bill de Blasio is basically talking to himself.