This is the DOT press release:

The New York City Department of Transportation (DOT) announced that beginning Sunday, October 15, the lower roadway of the Manhattan Bridge will be closed for the next year. During these twelve months all three lanes of the lower roadway will undergo a complete rehabilitation.

While the upper level of the Manhattan Bridge will remain open, DOT recommends that motorists use an alternate route to cross the East River during this closure. During the rehabilitation there will be no access to the lower roadway from either end of the bridge. All traffic will be directed to the upper roadways where two lanes will be maintained in both directions at all times. Pedestrians and bicyclists will share access along the Manhattan Bridge’s South walkway since the North bikeway will be closed. New York City Transit service on the bridge will not be affected. To help distribute traffic amongst the other East River crossings, the North Outer Roadway on the Williamsburg Bridge will be open to truck traffic.