The Canadian government has agreed to finance the construction of the $1-billion New International Trade Crossing, which would open in 2020.
The total cost of the project would be about $4 billion, including work on freeway interchanges, customs plazas in both countries and infrastructure work.
The final permit for the project was issued last month after a U.S. court rejected a request for an injunction filed by the private company that owns the existing Ambassador Bridge.
The next step involves securing funding for a U.S. customs facility, along with acquiring land on the American side.
Ambassador Bridge owner Matty Moroun has fought the proposal for years, instead pushing for the building of an additional span to his private bridge.
Raitt's office says the minister will make the announcement at a news conference in Windsor at 10:30 a.m.
Note to readers: This is a corrected story. A previous version gave an incorrect figure for the cost of the bridge.