The Alameda tunnel, built under the city of Alameda, is getting a $40 million injection of money from the California Department of Transportation and the California State Transportation Agency.
The tunnel will be the largest of its kind in the United States and will stretch about 12 miles.
Construction is expected to begin in the spring of 2019.
The Alameda Tunnel, also known as the Caltrans Alameda Treadway, is expected be completed in 2021.
The tunnel is expected reduce congestion for drivers, and the tunnel will create new access to the city’s downtown.
The $40.5 million tunnel is being funded by $20 million in federal and state grants and $5 million in local funds, the department said.
The state Transportation Department has awarded $5.2 million in matching funds.
A $2.2 billion tunnel project to connect downtown Los Angeles to the Pacific Ocean in 2019 is also expected to be completed this year, officials said.