Drivers heading west must go left on Atlantic and right on Third Avenue to reach Flatbush, while those heading to the area around Atlantic Terminal must make a right on Pacific Street, which has reversed direction, then a hard left at Pacific Street.
NY1 reported Atlantic Yards Project Causes Traffic Woes. CBS New York, with WINS, reported New Traffic Patterns Cause Confusion Near Atlantic Yards Project.
Atlantic Yards Watch (which supplied the photo, by Wayne Bailey), drivers were confused:
The traffic mitigations are being put in place at this time because traffic levels are lower than at other times of the year. The changes in traffic patterns, (actually implemented Saturday), are forced into being by temporary obstructions that will soon be turned into a permanent extended plaza on 4th Avenue between Atlantic and Flatbush, and a "neck-down" at Pacific and Flatbush.