GRAND RAPIDS, Mich. (WOOD) — Ambassador Bridge, one of the busiest international border crossings in the United States, was brought to a standstill Monday night by demonstrators protesting a new vaccine mandate for truck drivers.

The bridge has reopened for U.S. bound traffic, but remains closed for people trying to get from Detroit to Canada. Drivers either have to take the tunnel or cross in Port Huron.

The standstill left thousands of trucks stranded, and the ripple effects of even a temporary closure remain to be seen.

The Grand Rapids Chamber expressed concern about the possible impact the bridge closure could have on local stores and businesses.

“A significant percentage of jobs in West Michigan have an important reliance on a well-functioning border,” said Josh Lunger, the vice president of government affairs for the Grand Rapids Chamber.

Lunger said even the brief shutdown could further complicate ongoing supply chain issues.

“The impact on just-in-time deliveries and the ramifications across automobile manufacturers all the way down to their suppliers,” he said.

Lunger said the closure underscores the importance of investing in stronger infrastructure between Michigan and Canada.

“This further highlights why we’ve been supportive of the Gordie Howe International Bridge, because having … that express route strengthens our economy and it gives us a better connection to our single largest trade partner,” Lunger said.

Construction on the bridge connecting Detroit and Windsor broke ground in 2018 and is expected to open by the end of 2024.