(Aug. 5) DETROIT -- The two Detroit-Windsor border crossings of Southeast Michigan/Southwest Ontario are the busiest international crossings on the North American continent.

Truck traffic at the port has more than doubled from 2.5 million vehicles in 1990 to 5.1 million in 2000, according to the Detroit-Windsor Corridor Traffic Study, a joint effort of Michigan Department of Transportation and Transport Canada.

However, with the imposition of new customs regulations by the Office of Homeland Security, shippers are now complaining of lines, some as long as seven hours, where trucks stand idle just trying to get on the Detroit-Windsor bridge.

The complaints have accelerated calls for a third crossing into Canada.

In December 2000, the U.S. Federal Highway Administration, Transport Canada, the Michigan Department of Transportation and Ontario's Ministry of Transportation formed an Ontario-Michigan Border Transportation Partnership. The coalition of officials from both countries predict it will cost Michigan and Ontario more than $6 billion in lost jobs and commerce by 2030 if nothing is done to ease congestion.

Canadian/U.S. trade is the largest bilateral relationship in the world. U.S. Department of Commerce figures show that U.S. merchandise trade with Canada totaled $330 billion in 1999, up 20% from 1995.

Forty-two percent, $140 billion in 1999, of that trade crosses at the Detroit-Windsor border, and trucks carry 75% of the total. The Corridor Traffic Study predicts truck traffic will rise by 22% by 2021, resulting in 8.3 million truck crossings each year.