Construction crews work Friday on a joint on the Wilfred Avenue overpass on Highway 101 in Rohnert Park. Photo by Peter Fremgen

The widening of Highway 101 is about to take some big leaps forward.

–This week, weather permitting, Caltrans says, construction crews will begin the final paving of 101 from Rohnert Park Expressway to Petaluma Boulevard North, doing the work overnight to limit traffic delays. Northbound work is scheduled for 7 p.m. to 6 a.m., while southbound is 7 p.m. to 5 a.m., ending an hour earlier to get out of the way of commuters. At some point the paving will be done six days a week to speed things up, with a completion date of late July. Some lanes will be closed during the paving hours.

The paving will eliminate the uneven pavement through Rohnert Park and over the Cotati Grade that many Road Warrior readers have complained about.

–Then around June 15, Caltrans plans to open up the new Golf Course Drive segment under Highway 101 that will connect to Wilfred Avenue, giving drivers another way to get from one side of Rohnert Park to the other.

–In late August or early September, the new Wilfred Avenue/Commerce Boulevard overpasses on 101 will open, meaning drivers no longer will be squeezed into two lanes between the K-rails and instead will have three lanes in both directions. The third lane will be the carpool lane during commute hours, allowing carpoolers to speed by other drivers from about Petaluma Boulevard North to downtown Windsor.

–The remodeling of the East Washington Street interchange in Petaluma is ahead of schedule, so it may open sooner than the May 2014 completion target, Caltans officials said Friday during a media briefing on the 101 projects.

The next big step in the $8.3 million remodeling will come in late July when four girders weighing 76.5 tons each are expected to be erected over Washington Creek as a bridge for a new northbound onramp that will run behind the Raley’s shopping center. The onramp will gradually drop to the highway’s level to allow traffic to merge onto 101 south of Lynch Creek.

Once the remodeling is completed, westbound traffic on East Washington will have to use the new onramp to go north on 101. The existing left turn onto the current northbound onramp will be eliminated. Eastbound traffic will continue to be able to use the current onramp.

–The planned renovation and expansion of the Petaluma Boulevard North/Old Redwood Highway interchange on 101 is hung up because of a battle between Petaluma and the state Department of Finance over whether the city can go ahead with contributing millions in redevelopment money for the project, Caltrans officials said.

–In Marin, the next stage in widening 101 — from Atherton Avenue to the Birkenstocks building — is expected to start this fall with completion next year, Caltrans said.

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