SEATTLE (AP) — The Seattle Transportation Department reports progress in addressing a traffic problem known as the Mercer Mess.

On Sunday night crews opened two-way traffic on Mercer with three lanes in each direction in the South Lake Union area between Interstate 5 and the Seattle Center. Traffic has been congested for decades in the area, which also is home to Amazon offices and biotech businesses.

The route handles about 80,000 vehicles a day. Work continues with some nearby streets closed for additional improvements.