DETROIT — Eroding auto parts traffic between the U.S. and Canada is reducing the need for two new international bridge crossings between Windsor and Detroit, says a study backed by the Detroit Regional Chamber.

Matty Moroun — the owner of the private Ambassador Bridge who’s fighting plans to build a second, government-backed bridge downriver — has been saying the same things for years.

Trouble is, the authors of the report appear to be referring to his twin Ambassador span as redundant.

Moroun, of course is forging ahead with plans to build a second bridge adjacent to the Ambassador at the same time the Detroit River International Crossing (DRIC), a partnership between the U.S and Canadian governments, is proposing a separate bridge about 3 kilometers southwest of the Ambassador. 

The study — titled "Toward a New Frontier: Improving the U.S.-Canadian Border" and authored by the conservative-leaning think tank, the Brookings Institution — states that the additional capacity can’t be supported going forward because of the changing North American auto industry landscape.

Although the Ambassador carries more trade between the United States and Canada than flows between the U.S. and all of Europe and Japan combined, the study notes that commercial traffic on the current Ambassador has fallen over 30 percent since 2007.

According to a report in the Detroit News, the report states that the general slowdown in north-south trade "casts doubt" on the economic need for a second new crossing.

"Declining traffic figures … undermine the case for the investment of billions of dollars in new border infrastructure after years of contentious debate and planning have already taken place," the report says.

However, the study reportedly favors going ahead with the DRIC bridge to eventually replace the aging, 81-year-old Ambassador.

John Austin, co-director of Brookings Institution’s Great Lakes Economic Initiative, says the White House needs to "throw its weight" behind the DRIC efforts to build a second span. 

Chamber President Richard Blouse said he plans to send the 40-page study to President Obama and PM Minister Stephen Harper.