As construction workers continue to complete new sections of Highway 101 along the Novato Narrows, Caltrans is preparing to shift northbound lanes of traffic to a new alignment.

The switch will take place overnight Friday and is slated to be completed for motorists traveling early Saturday, according to a Caltrans news release.

The new alignment will take place from the San Antonio Road/Landfill exit in the south to Kastania/Petaluma Boulevard exit in the north.

An accompanying photo indicated the alignment will shift the lanes west, closer to southbound traffic. A series of concrete barriers will separate northbound and southbound vehicles.

Safety signs and message boards will alert motorists to the lane shift.

The entire Narrows project extends 17 miles from Highway 37 in Novato to Old Redwood Highway in Petaluma.

When completed, the freeway will include six lanes of travel, of which two will be designated for high occupancy vehicles during commute hours.