Caltrans has updated its timeline for changes in the Rohnert Park-to-Cotati-to-Petaluma construction zone of Highway 101.

For widening 101 from Pepper Road south to Petaluma Boulevard North, K-rails have been going up along the road but Caltrans spokesman Bob Haus said construction will really begin around mid-July.

The new Wilfred Avenue overpass, which was due to open in early July, now is expected to open up to traffic on July 22.

The new Wilfred Avenue exit for southbound 101 is expected to open around Aug. 1.