Trucks are lined bumper-to-bumper in two of three northbound lanes on Huron Church Road, leading to the Ambassador Bridge.
"We have been experiencing computer problems since this morning. The exact cause has not been determined," U.S. Customs and Border Protection spokesman Ken Hammond said in an email to CBC News just before 2 p.m. "We are working diligently to restore our systems and are still processing travellers and commercial vehicles."
Ontario Provincial Police tweeted that traffic is at a standstill along North America's busiest land border crossing.
Drivers of cars and trucks are being warned by U.S. officials on the U.S. Customs and Border Protection's border wait time website that it will take more than two hours to cross into Detroit from Windsor, Ont.
Some truckers are worried they will have to spend the night in a hotel or in parking lots because of provincial regulations that prohibit them from driving more than 11 hours in one day.
Peter Plaskota was coming from Toronto to Toledo, Ohio, about 45 minutes outside of Detroit. He’s been driving for 27 years. He hasn’t been in a delay this long since Sept. 11, 2001, immediately after terrorists flew planes into the World Trade Centre in New York.
“What can I say? We have to run with our log book. We cannot go any farther than our log book allows us. It looks like I won’t be home tonight. I’m almost on the limit. Everyone in this line has a log book.”
On the Ambassador Bridge's live web camera, trucks can be seen lined up waiting to clear customs.
The Windsor-Detroit corridor is crucial to the economic prosperity of both Canada and the U.S. Approximately 30 per cent of trade between Canada and the U.S. flowed through Windsor-Detroit last year, accounting for $20 billion in goods hauled by 2.4 million trucks.
Traffic is so heavy that a local school board took to Twitter warning that students may have trouble getting home on time.