How The Trucker Protests Are Snarling the Auto Industry

“What people seem to not understand is that when that truck isn’t moving, they make no money,” Ms. Walker said, noting that drivers with certain types of cargo, such as some hazardous materials, are limited to crossing on the Ambassador Bridge.

The slowdown in Canadian trade will disproportionately affect New York, Michigan and Ohio, said Arthur Wheaton, the director of labor studies at Cornell’s School of Industrial and Labor Relations. At the same time, he added, the protests were “certainly raising concerns for all U.S. manufacturers.”

“There is already a shortage of truck drivers in North America, so protests keeping truckers off their routes exacerbates problems for an already fragile supply chain,” Mr. Wheaton said.

Carmakers had hoped that shortages of computer chips and other components would ease this year, allowing them to concentrate on the long-term: the transition to electric vehicles.

A larger fear for many elected officials and business executives is that the scene at the Ambassador Bridge could inspire other protests. The Department of Homeland Security warned in an internal memo that a convoy of protesting truckers was planning to travel from California to Washington, D.C., potentially disrupting the Super Bowl and President Biden’s State of the Union address on March 1.

“While there are currently no indications of planned violence,” the memo, which was dated Tuesday, said, “if hundreds of trucks converge in a major metropolitan city, the potential exists to severely disrupt transportation, federal government operations, commercial facilities and emergency services through gridlock and potential counter protests.”

Mr. Chiodo, the Canadian union leader, said that “the people who are demonstrating are doing it for the wrong reasons. They want to get back to the way things were before the pandemic, and in reality they are shutting things down.”