DETROIT—U.S. and Canadian officials rolled out Friday a new plan to build a second bridge between Detroit and Windsor, Ontario, to speed the flow of goods through one of North America's busiest border crossings.

"We have reached an agreement to build the long awaited Detroit River International Crossing," Canadian Prime Minister Stephen Harper said in Windsor Friday afternoon. "This is a really large project, even for countries the size of the United States and Canada."

The linchpin of the bridge proposal is a deal that relies on private financing and as much as $550 million from the Canadian government, people familiar with the matter said. It is expected the plan would involve no public funds from Michigan.

Terms of the deal call for the Canadian government to establish a "Crossing Authority" that will be responsible for building and operating the new bridge in partnership with a private entity. The contractor will be selected by a new international authority with three members each from Michigan and Canada, according to a draft reviewed by The Wall Street Journal. The Detroit News and Detroit Free Press reported terms of the agreement on Friday.

The company that builds the bridge will get payments from Canada over a 40 to 50 year period, with the money coming from tolls collected on the Canadian side of the bridge. No tolls will be levied on the U.S. side, according to a draft of the agreement. Michigan won't use any public funds to build or operate the bridge—a provision made necessary by opposition to the project from Republicans who control the state legislature.