After blocking streets in the capital Ottawa for 10 days, the truckers brought their anti-government blockade to the Ambassador Bridge, which links Windsor, Ontario, with the city of Detroit.

Each day, $300 million worth of car and truck parts, agricultural products, steel and other raw materials flows across the bridge, according to Flavio Volpe, president of the Auto Parts Manufacturers Association in Toronto.

U.S. manufacturers rely on daily or near-daily shipments to and from their Canadian partners. Just one or two more days of interrupted deliveries could lead to temporary layoffs or plant closures, Volpe said.

“We work in 24-48 hour contingencies. Everybody is thinking about what that means for tomorrow’s production,” he said. “A few dozen people are getting in the way of the American economy.”