Highway 101 Narrows project awarded $40 million for final leg between Sonoma, Marin counties

State transportation officials on Wednesday awarded more than $40 million to Marin County to complete the last segment of the Highway 101 Sonoma-Marin Narrows lane-widening project.

The grant will go toward constructing a third lane in both directions of the highway from Novato to just south of the Sonoma-Marin county line. The project is estimated to cost almost $136 million and begin in the spring, with a three-year buildout.

The 6-mile southbound and 3½-mile northbound stretches along Highway 101 in Marin County will follow up on a segment currently under construction in Sonoma County from the Petaluma River north to Corona Road. That more than 3-mile stretch, at a cost of $121 million, is scheduled to be finished by the end of 2022.

All told, the 17-mile Sonoma-Marin Narrows project is on target to cost up to $754 million and be completed by late 2023 or early 2024.

You can reach Staff Writer Kevin Fixler at 707-521-5336 or kevin.fixler@pressdemocrat.com. On Twitter @kfixler.