The California Transportation Commission on Wednesday approved $53 million for a project designed to help eliminate the Highway 12/Jameson Canyon bottleneck at Interstate 80.

Construction to create a two-lane ramp from eastbound Highway 12 to eastbound I-80 could begin in 2020, Solano Transportation Authority Executive Director Daryl Halls said. He estimated the project will cost about $70 million, with the remaining money coming from other sources.

Caltrans in 2014 finished widening Highway 12 from two to four lanes along the six-mile Jameson Canyon segment. But the two eastbound lanes squeeze down to one lane at the interchange ramp, causing backups that commuters say can top a mile.

Although the planned project is in Solano County, it is only three miles east of the Napa County line. Highway 12 through Jameson Canyon is a major link between Napa and Solano counties.

The $53 million for ramp improvements comes from last year’s Senate Bill 1, which among other things boosted the state excise gas tax by 12 cents per gallon. The California Transportation Commission on Wednesday awarded a total of $660 million from the new funding source to 13 Bay Area transportation projects, a Metropolitan Transportation Commission press release said.

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Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He has worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield.