Upper Wacker Drive opened completely to traffic around noon Friday; Lower Wacker Drive followed, opening completely just a few hours later.
"Six-thousand vehicles use Wacker on a daily basis and 150,000 pedestrians, so I think with the improvements that have been made, the flow of traffic is going to be a lot easier," said Ann Schneider, Illinois Secretary of Transportation.
The most noticeable change in the north/south stretch of the new Wacker Drive is the elimination of all but two access ramps between the upper and lower levels- one southbound at Randolph, and one northbound at Monroe. Fewer merge points should ease congestion and improve safety.
One of the biggest changes in the reconstruction is where Lower Wacker Drive merges onto the outbound Eisenhower. In the old design, traffic from Lower Wacker as well as from Franklin merged into the outbound Eisenhower, but the new design is wider and safer.
"There's going to be a dedicated merge lane now when you're coming off Wacker onto the Eisenhower that's going to be a much safer movement for motorists, they'll have a lane to accelerate in before they have to merge into traffic," said Schneider.
There are more improvements to Lower Wacker. The vertical clearance is one foot higher. The service lanes are separated from through traffic to ease congestion. The lighting is brighter and a new ventilation system will improve air quality.
Coordinating a project of this magnitude was complicated, dealing with a double-decker roadway, as well reconstructing the viaducts and bridges that connect to the east-west portion of Wacker Drive.
Because of new construction technology, officials expect the new Wacker Drive to last for 100 years.
"If you invest in your infrastructure, your roads, your rails and your runways, there is nobody that will ever beat the City of Chicago when it comes to the modern economy," said Mayor Rahm Emanuel.
Governor Pat Quinn joined Emanuel to celebrate Friday morning, shaking hands with workers and transportation officials.