Steel cables are being used to slowly lower the span approximately 125 feet -- an estimated 20 feet per hour. The entire operation is expected to last approximately 16 to 18 hours.
It is part an overall $873 million investment to replace the Kosciuszko Bridge with two new state-of-the-art, cable-stayed bridges.
Ultimately, the span is expected to accommodate 180,000 cars per day.
By comparison, the original bridge, opened in 1939, was built for only 10,000.
The new span will eventually offer a bike and pedestrian lane, as well as shoulders for emergencies, and will also be more viable for trucks as the incline won't be as steep.