Auto production restarts after the Ambassador Bridge is cleared.

The North American auto industry lumbered back to life on Monday after Canadian authorities cleared protesters and vehicles from a key trade route between the United States and Canada that had been closed for nearly a week.

But some auto manufacturers said it would take several days for production to return to normal because it will take time to deliver necessary parts to factories. For some companies, a longer-term shortage of chips was still keeping plants closed.

“It’s not like you can flip a switch and get back to where we were production-wise,” said Peter Nagle, a principal analyst who specializes in the auto industry at IHS Markit, a research firm. “It’s going to take a few weeks.”

The blockade of the bridge, which connects Detroit to Windsor, Ontario, and other border crossings came after truckers and their allies paralyzed parts of Ottawa to protest vaccine mandates and other pandemic restrictions.

Ford Motor said it hadn’t seen any impact related to the border disruptions since Friday, but that an Ohio facility would be shut down this week because of the chip shortage. General Motors said its factories were operating normally on Monday.

Toyota said that it expected border-related disruptions to continue this week, but that some improvements were likely in the coming days as the supply chain catches up. The company’s facilities in Ontario, Kentucky, Alabama and West Virginia had recently been affected by border blockades, a representative for the company said.

Stellantis, which owns Jeep, Ram and other brands, said that it had cut short a number of shifts at U.S. and Canadian plants last week because of parts shortages caused by the blockade. Operations resumed Monday morning as scheduled, and the company is aiming to make up lost production in coming months, said Lou Ann Gosselin, a company spokeswoman.

“We are working with our carriers to get parts into the plants as quickly as possible to mitigate any further disruptions,” she said.

A representative for Unifor, a large Canadian union that represents autoworkers at many manufacturers, said auto production would likely return to normal within days.

But Mr. Nagle of IHS Markit said it would take longer than that, especially considering that carmakers were already struggling with shortages of semiconductors and other components.

Many of the suppliers hardest hit by the bridge blockade were small firms producing specialized components. Until these essential links in the supply chain ramp up production, the industry will not be able to function normally, Mr. Nagle said Monday.

Paul Ashworth, chief North America economist for Capital Economics, said that some Ford plants had reduced production this month because of chip shortages, “but the broader picture seems to be that the situation is improving.”

Congestion at the West Coast ports that handle chip imports has eased. And production at auto plants has been rebounding in recent months, though it remains a bit below normal. The latest sales figures show that new vehicle sales rebounded by about 20 percent in January, Mr. Ashworth said.

On Sunday night, police in Windsor, Ontario, said they had arrested several people and towed trucks parked in an intersection leading to the Ambassador Bridge. The bridge reopened just before midnight.